diff --git a/src/LMDB.jl b/src/LMDB.jl
index b5bc871..1b5eca7 100644
--- a/src/LMDB.jl
+++ b/src/LMDB.jl
@@ -7,7 +7,7 @@ module LMDB
                  isopen, count, delete!, info, get, show, convert
     import Base.Iterators: drop
 
-    depsfile = joinpath(dirname(@__FILE__),"..","deps","deps.jl")
+    depsfile = joinpath(dirname(@__FILE__), "..", "deps", "deps.jl")
     if isfile(depsfile)
         include(depsfile)
     else
diff --git a/src/dbi.jl b/src/dbi.jl
index abdb1bd..7b91ba9 100644
--- a/src/dbi.jl
+++ b/src/dbi.jl
@@ -80,9 +80,9 @@ function put!(txn::Transaction, dbi::DBI, key, val; flags::Cuint = zero(Cuint))
 end
 
 "Delete items from a database"
-function delete!(txn::Transaction, dbi::DBI, key, val)
+function delete!(txn::Transaction, dbi::DBI, key, val=C_NULL)
     mdb_key_ref = Ref(MDBValue(key))
-    mdb_val_ref = Ref(MDBValue(val))
+    mdb_val_ref = (val === C_NULL) ? C_NULL : Ref(MDBValue(val))
 
     ret = ccall((:mdb_del, liblmdb), Cint,
                 (Ptr{Void}, Cuint, Ptr{MDBValue}, Ptr{MDBValue}),
diff --git a/test/dbi.jl b/test/dbi.jl
index 5eab213..abb9b80 100644
--- a/test/dbi.jl
+++ b/test/dbi.jl
@@ -40,6 +40,7 @@ module LMDB_DBI
                     value = get(txn, dbi, k, String)
                     println("Got value for key $(k): $(value)")
                     @test value == val*string(k)
+                    delete!(txn, dbi, k)
                     k += 1
                     value = get(txn, dbi, k, String)
                     println("Got value for key $(k): $(value)")
@@ -60,4 +61,4 @@ module LMDB_DBI
     finally
         rm(dbname, recursive=true)
     end
-end
\ No newline at end of file
+end