diff --git a/lib/index.js b/lib/index.js
index be514d16a..a9feb90a1 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -150,6 +150,7 @@ function getOptions(options) {
 
   var error = options.error;
   var success = options.success;
+  var importer = options.importer;
 
   options.error = function(err, code) {
     try {
@@ -171,6 +172,17 @@ function getOptions(options) {
     }
   };
 
+  if (importer) {
+    options.importer = function(file, prev, key) {
+      importer(file, prev, function(data) {
+        binding.importedCallback({
+          index: key,
+          objectLiteral: data
+        });
+      });
+    };
+  }
+
   delete options.image_path;
   delete options.include_paths;
   delete options.includePaths;
diff --git a/src/binding.cpp b/src/binding.cpp
index 89e3469e8..417dcc6f7 100644
--- a/src/binding.cpp
+++ b/src/binding.cpp
@@ -1,44 +1,104 @@
 #include <nan.h>
+#include <vector>
 #include "sass_context_wrapper.h"
 
 char* CreateString(Local<Value> value) {
-  if(value->IsNull() || !value->IsString()) {
+  if (value->IsNull() || !value->IsString()) {
     return const_cast<char*>(""); // return empty string.
   }
 
   String::Utf8Value string(value);
-  char *str = (char *) malloc(string.length() + 1);
+  char *str = (char *)malloc(string.length() + 1);
   strcpy(str, *string);
   return str;
 }
 
-void ExtractOptions(Local<Object> options, void* cptr, sass_context_wrapper* ctx_w, bool isFile) {
-  if (ctx_w) {
-    NanAssignPersistent(ctx_w->stats, options->Get(NanNew("stats"))->ToObject());
+std::vector<sass_context_wrapper*> imports_collection;
 
-    // async (callback) style
-    Local<Function> callback = Local<Function>::Cast(options->Get(NanNew("success")));
-    Local<Function> errorCallback = Local<Function>::Cast(options->Get(NanNew("error")));
-    if (isFile) {
-      ctx_w->fctx = (struct Sass_File_Context*) cptr;
-    } else {
-      ctx_w->dctx = (struct Sass_Data_Context*) cptr;
-    }
-    ctx_w->request.data = ctx_w;
-    ctx_w->callback = new NanCallback(callback);
-    ctx_w->errorCallback = new NanCallback(errorCallback);
+void dispatched_async_uv_callback(uv_async_t *req){
+  NanScope();
+  sass_context_wrapper* ctx_w = static_cast<sass_context_wrapper*>(req->data);
+
+  TryCatch try_catch;
+
+  imports_collection.push_back(ctx_w);
+
+  Handle<Value> argv[] = {
+    NanNew<String>(strdup(ctx_w->file)),
+    NanNew<String>(strdup(ctx_w->prev)),
+    NanNew<Number>(imports_collection.size() - 1)
+  };
+
+  NanNew<Value>(ctx_w->importer_callback->Call(3, argv));
+
+  if (try_catch.HasCaught()) {
+    node::FatalException(try_catch);
+  }
+}
+
+struct Sass_Import** sass_importer(const char* file, const char* prev, void* cookie)
+{
+  sass_context_wrapper* ctx_w = static_cast<sass_context_wrapper*>(cookie);
+
+  ctx_w->file = strdup(file);
+  ctx_w->prev = strdup(prev);
+  ctx_w->async.data = (void*)ctx_w;
+  uv_async_send(&ctx_w->async);
+
+  if (ctx_w->success_callback) {
+    /*  that is async: Render() or RenderFile(),
+     *  the default even loop is unblocked so it
+     *  can run uv_async_send without a push.
+     */
+    uv_cond_wait(&ctx_w->importer_condition_variable, &ctx_w->importer_mutex);
+  }
+  else{
+    /*  that is sync: RenderSync() or RenderFileSync,
+     *  we need to explicitly uv_run as the event loop
+     *  is blocked; waiting down the chain.
+     */
+    uv_run(ctx_w->async.loop, UV_RUN_DEFAULT);
   }
 
+  return ctx_w->imports;
+}
+
+void ExtractOptions(Local<Object> options, void* cptr, sass_context_wrapper* ctx_w, bool isFile, bool isSync) {
   struct Sass_Context* ctx;
 
   if (isFile) {
     ctx = sass_file_context_get_context((struct Sass_File_Context*) cptr);
-  } else {
+    ctx_w->fctx = (struct Sass_File_Context*) cptr;
+  }
+  else {
     ctx = sass_data_context_get_context((struct Sass_Data_Context*) cptr);
+    ctx_w->dctx = (struct Sass_Data_Context*) cptr;
   }
 
   struct Sass_Options* sass_options = sass_context_get_options(ctx);
 
+  if (!isSync) {
+    NanAssignPersistent(ctx_w->stats, options->Get(NanNew("stats"))->ToObject());
+
+    ctx_w->request.data = ctx_w;
+
+    // async (callback) style
+    Local<Function> success_callback = Local<Function>::Cast(options->Get(NanNew("success")));
+    Local<Function> error_callback = Local<Function>::Cast(options->Get(NanNew("error")));
+
+    ctx_w->success_callback = new NanCallback(success_callback);
+    ctx_w->error_callback = new NanCallback(error_callback);
+  }
+
+  Local<Function> importer_callback = Local<Function>::Cast(options->Get(NanNew("importer")));
+
+  ctx_w->importer_callback = new NanCallback(importer_callback);
+
+  if (!importer_callback->IsUndefined()) {
+    uv_async_init(uv_default_loop(), &ctx_w->async, (uv_async_cb)dispatched_async_uv_callback);
+    sass_option_set_importer(sass_options, sass_make_importer(sass_importer, ctx_w));
+  }
+
   sass_option_set_output_path(sass_options, CreateString(options->Get(NanNew("outFile"))));
   sass_option_set_image_path(sass_options, CreateString(options->Get(NanNew("imagePath"))));
   sass_option_set_output_style(sass_options, (Sass_Output_Style)options->Get(NanNew("style"))->Int32Value());
@@ -56,7 +116,7 @@ void FillStatsObj(Handle<Object> stats, Sass_Context* ctx) {
   char** included_files = sass_context_get_included_files(ctx);
   Handle<Array> arr = NanNew<Array>();
 
-  if(included_files) {
+  if (included_files) {
     for (int i = 0; included_files[i] != nullptr; ++i) {
       arr->Set(i, NanNew<String>(included_files[i]));
     }
@@ -72,14 +132,15 @@ void FillStatsObj(Handle<Object> stats, Sass_Context* ctx) {
 
   if (sass_context_get_source_map_string(ctx)) {
     source_map = NanNew<String>(sass_context_get_source_map_string(ctx));
-  } else {
+  }
+  else {
     source_map = NanNew<String>("{}");
   }
 
-  (*stats)->Set(NanNew("sourceMap"), source_map); 
+  (*stats)->Set(NanNew("sourceMap"), source_map);
 }
 
-void MakeCallback(uv_work_t* req) {
+void make_callback(uv_work_t* req) {
   NanScope();
 
   TryCatch try_catch;
@@ -91,7 +152,8 @@ void MakeCallback(uv_work_t* req) {
     ctx = sass_data_context_get_context(ctx_w->dctx);
     FillStatsObj(NanNew(ctx_w->stats), ctx);
     error_status = sass_context_get_error_status(ctx);
-  } else {
+  }
+  else {
     ctx = sass_file_context_get_context(ctx_w->fctx);
     FillStatsObj(NanNew(ctx_w->stats), ctx);
     error_status = sass_context_get_error_status(ctx);
@@ -104,15 +166,16 @@ void MakeCallback(uv_work_t* req) {
       NanNew<String>(val),
       NanNew(ctx_w->stats)->Get(NanNew("sourceMap"))
     };
-    ctx_w->callback->Call(2, argv);
-  } else {
+    ctx_w->success_callback->Call(2, argv);
+  }
+  else {
     // if error, do callback(error)
     const char* err = sass_context_get_error_json(ctx);
     Local<Value> argv[] = {
       NanNew<String>(err),
       NanNew<Integer>(error_status)
     };
-    ctx_w->errorCallback->Call(2, argv);
+    ctx_w->error_callback->Call(2, argv);
   }
   if (try_catch.HasCaught()) {
     node::FatalException(try_catch);
@@ -129,11 +192,9 @@ NAN_METHOD(Render) {
   struct Sass_Data_Context* dctx = sass_make_data_context(source_string);
   sass_context_wrapper* ctx_w = sass_make_context_wrapper();
 
-  ctx_w->dctx = dctx;
+  ExtractOptions(options, dctx, ctx_w, false, false);
 
-  ExtractOptions(options, dctx, ctx_w, false);
-
-  int status = uv_queue_work(uv_default_loop(), &ctx_w->request, compile_it, (uv_after_work_cb)MakeCallback);
+  int status = uv_queue_work(uv_default_loop(), &ctx_w->request, compile_it, (uv_after_work_cb)make_callback);
 
   assert(status == 0);
 
@@ -147,8 +208,9 @@ NAN_METHOD(RenderSync) {
   char* source_string = CreateString(options->Get(NanNew("data")));
   struct Sass_Data_Context* dctx = sass_make_data_context(source_string);
   struct Sass_Context* ctx = sass_data_context_get_context(dctx);
+  sass_context_wrapper* ctx_w = sass_make_context_wrapper();
 
-  ExtractOptions(options, dctx, NULL, false);
+  ExtractOptions(options, dctx, ctx_w, false, true);
   compile_data(dctx);
   FillStatsObj(options->Get(NanNew("stats"))->ToObject(), ctx);
 
@@ -161,7 +223,7 @@ NAN_METHOD(RenderSync) {
 
   Local<String> error = NanNew<String>(sass_context_get_error_json(ctx));
 
-  sass_delete_data_context(dctx);
+  sass_free_context_wrapper(ctx_w);
   NanThrowError(error);
 
   NanReturnUndefined();
@@ -175,10 +237,9 @@ NAN_METHOD(RenderFile) {
   struct Sass_File_Context* fctx = sass_make_file_context(input_path);
   sass_context_wrapper* ctx_w = sass_make_context_wrapper();
 
-  ctx_w->fctx = fctx;
-  ExtractOptions(options, fctx, ctx_w, true);
+  ExtractOptions(options, fctx, ctx_w, true, false);
 
-  int status = uv_queue_work(uv_default_loop(), &ctx_w->request, compile_it, (uv_after_work_cb)MakeCallback);
+  int status = uv_queue_work(uv_default_loop(), &ctx_w->request, compile_it, (uv_after_work_cb)make_callback);
 
   assert(status == 0);
   free(input_path);
@@ -193,8 +254,9 @@ NAN_METHOD(RenderFileSync) {
   char* input_path = CreateString(options->Get(NanNew("file")));
   struct Sass_File_Context* fctx = sass_make_file_context(input_path);
   struct Sass_Context* ctx = sass_file_context_get_context(fctx);
+  sass_context_wrapper* ctx_w = sass_make_context_wrapper();
 
-  ExtractOptions(options, fctx, NULL, true);
+  ExtractOptions(options, fctx, ctx_w, true, true);
   compile_file(fctx);
   FillStatsObj(options->Get(NanNew("stats"))->ToObject(), ctx);
   free(input_path);
@@ -208,17 +270,83 @@ NAN_METHOD(RenderFileSync) {
 
   Local<String> error = NanNew<String>(sass_context_get_error_json(ctx));
 
-  sass_delete_file_context(fctx);
+  sass_free_context_wrapper(ctx_w);
   NanThrowError(error);
 
   NanReturnUndefined();
 }
 
+NAN_METHOD(ImportedCallback) {
+  NanScope();
+
+  TryCatch try_catch;
+
+  Local<Object> options = args[0]->ToObject();
+  char* source_string = CreateString(options->Get(NanNew("index")));
+  Local<Value> returned_value = options->Get(NanNew("objectLiteral"));
+
+  size_t index = options->Get(NanNew("index"))->Int32Value();
+
+  if (index >= imports_collection.size()) {
+    NanReturnUndefined();
+  }
+
+  sass_context_wrapper* ctx_w = imports_collection[index];
+
+  if (returned_value->IsArray()) {
+    Handle<Array> array = Handle<Array>::Cast(returned_value);
+
+    ctx_w->imports = sass_make_import_list(array->Length());
+
+    for (size_t i = 0; i < array->Length(); ++i) {
+      Local<Value> value = array->Get(i);
+
+      if (!value->IsObject())
+        continue;
+
+      Local<Object> object = Local<Object>::Cast(value);
+      char* path = CreateString(object->Get(String::New("file")));
+      char* contents = CreateString(object->Get(String::New("contents")));
+
+      ctx_w->imports[i] = sass_make_import_entry(path, (!contents || contents[0] == '\0') ? 0 : strdup(contents), 0);
+    }
+  }
+  else if (returned_value->IsObject()) {
+    ctx_w->imports = sass_make_import_list(1);
+    Local<Object> object = Local<Object>::Cast(returned_value);
+    char* path = CreateString(object->Get(String::New("file")));
+    char* contents = CreateString(object->Get(String::New("contents")));
+
+    ctx_w->imports[0] = sass_make_import_entry(path, (!contents || contents[0] == '\0') ? 0 : strdup(contents), 0);
+  }
+  else {
+    ctx_w->imports = sass_make_import_list(1);
+    ctx_w->imports[0] = sass_make_import_entry(ctx_w->file, 0, 0);
+  }
+
+  uv_cond_signal(&ctx_w->importer_condition_variable);
+
+  if (try_catch.HasCaught()) {
+    node::FatalException(try_catch);
+  }
+
+  if (!ctx_w->success_callback) {
+    /*
+     *  that is sync: RenderSync() or RenderFileSync,
+     *  we ran it explictly, so we stop it similarly.
+     */
+    uv_stop(ctx_w->async.loop);
+  }
+
+  NanReturnValue(NanNew<Number>(0));
+}
+
 void RegisterModule(v8::Handle<v8::Object> target) {
   NODE_SET_METHOD(target, "render", Render);
   NODE_SET_METHOD(target, "renderSync", RenderSync);
   NODE_SET_METHOD(target, "renderFile", RenderFile);
   NODE_SET_METHOD(target, "renderFileSync", RenderFileSync);
+  NODE_SET_METHOD(target, "importedCallback", ImportedCallback);
 }
 
 NODE_MODULE(binding, RegisterModule);
diff --git a/src/libsass b/src/libsass
index 5f3558d7c..7aaa45a97 160000
--- a/src/libsass
+++ b/src/libsass
@@ -1 +1 @@
-Subproject commit 5f3558d7ce36bb61202f1585ed8e32a52209e940
+Subproject commit 7aaa45a979ce65d50b3158ff50bf9409f8955063
diff --git a/src/sass_context_wrapper.cpp b/src/sass_context_wrapper.cpp
index 5f29b0d1c..35023e1b1 100644
--- a/src/sass_context_wrapper.cpp
+++ b/src/sass_context_wrapper.cpp
@@ -8,7 +8,8 @@ extern "C" {
 
     if (ctx_w->dctx) {
       compile_data(ctx_w->dctx);
-    } else if (ctx_w->fctx) {
+    }
+    else if (ctx_w->fctx) {
       compile_file(ctx_w->fctx);
     }
   }
@@ -22,19 +23,31 @@ extern "C" {
   }
 
   sass_context_wrapper* sass_make_context_wrapper() {
-    return (sass_context_wrapper*) calloc(1, sizeof(sass_context_wrapper));
+    auto ctx_w = (sass_context_wrapper*)calloc(1, sizeof(sass_context_wrapper));
+    uv_mutex_init(&ctx_w->importer_mutex);
+    uv_cond_init(&ctx_w->importer_condition_variable);
+    return ctx_w;
   }
 
   void sass_free_context_wrapper(sass_context_wrapper* ctx_w) {
     if (ctx_w->dctx) {
       sass_delete_data_context(ctx_w->dctx);
-    } else if (ctx_w->fctx) {
+    }
+    else if (ctx_w->fctx) {
       sass_delete_file_context(ctx_w->fctx);
     }
 
     NanDisposePersistent(ctx_w->stats);
-    delete ctx_w->callback;
-    delete ctx_w->errorCallback;
+
+    delete ctx_w->success_callback;
+    delete ctx_w->error_callback;
+    delete ctx_w->importer_callback;
+    delete ctx_w->file;
+    delete ctx_w->prev;
+    delete ctx_w->cookie;
+
+    uv_mutex_destroy(&ctx_w->importer_mutex);
+    uv_cond_destroy(&ctx_w->importer_condition_variable);
 
     free(ctx_w);
   }
diff --git a/src/sass_context_wrapper.h b/src/sass_context_wrapper.h
index a4c106a6b..902a70df1 100644
--- a/src/sass_context_wrapper.h
+++ b/src/sass_context_wrapper.h
@@ -5,23 +5,31 @@
 extern "C" {
 #endif
 
-using namespace v8;
+  using namespace v8;
 
-void compile_data(struct Sass_Data_Context* dctx);
-void compile_file(struct Sass_File_Context* fctx);
-void compile_it(uv_work_t* req);
+  void compile_data(struct Sass_Data_Context* dctx);
+  void compile_file(struct Sass_File_Context* fctx);
+  void compile_it(uv_work_t* req);
 
-struct sass_context_wrapper {
-  Sass_Data_Context* dctx;
-  Sass_File_Context* fctx;
-  Persistent<Object> stats;
-  uv_work_t request;
-  NanCallback* callback;
-  NanCallback* errorCallback;
-};
+  struct sass_context_wrapper {
+    Sass_Data_Context* dctx;
+    Sass_File_Context* fctx;
+    Persistent<Object> stats;
+    uv_work_t request;
+    uv_mutex_t importer_mutex;
+    uv_cond_t importer_condition_variable;
+    uv_async_t async;
+    const char* file;
+    const char* prev;
+    void* cookie;
+    Sass_Import** imports;
+    NanCallback* success_callback;
+    NanCallback* error_callback;
+    NanCallback* importer_callback;
+  };
 
-struct sass_context_wrapper*      sass_make_context_wrapper(void);
-void sass_free_context_wrapper(struct sass_context_wrapper* ctx_w);
+  struct sass_context_wrapper*      sass_make_context_wrapper(void);
+  void sass_free_context_wrapper(struct sass_context_wrapper* ctx_w);
 
 #ifdef __cplusplus
 }
diff --git a/test/fixtures/spec b/test/fixtures/spec
index b85c617a0..074ae3b24 160000
--- a/test/fixtures/spec
+++ b/test/fixtures/spec
@@ -1 +1 @@
-Subproject commit b85c617a0e7e5367dd347b0b301ad1c15b6d5087
+Subproject commit 074ae3b24bfc3ff19a98efdec02415ed6fd5759a