diff --git a/elf/Versions b/elf/Versions
index c5613942..8d7bac5d 100644
--- a/elf/Versions
+++ b/elf/Versions
@@ -178,6 +178,7 @@ ld {
     __nacl_irt_shmctl;
     __nacl_irt_rename;
     __nacl_irt_chmod;
+    __nacl_irt_fchmod;
     
     # Those are in the dynamic linker, but used by libc.so.
     __libc_enable_secure;
diff --git a/sysdeps/nacl/irt_syscalls.c b/sysdeps/nacl/irt_syscalls.c
index 4f8e2c85..02d3548e 100644
--- a/sysdeps/nacl/irt_syscalls.c
+++ b/sysdeps/nacl/irt_syscalls.c
@@ -368,6 +368,7 @@ int (*__nacl_irt_mkdir) (const char* pathname, mode_t mode);
 int (*__nacl_irt_rmdir) (const char* pathname);
 int (*__nacl_irt_chdir) (const char* pathname);
 int (*__nacl_irt_chmod) (const char* pathname, mode_t mode);
+int (*__nacl_irt_fchmod) (int fd, mode_t mode);
 int (*__nacl_irt_getuid) (void);
 int (*__nacl_irt_geteuid) (void);
 int (*__nacl_irt_getgid) (void);
@@ -537,6 +538,11 @@ static int nacl_irt_chmod (const char *pathname, mode_t mode)
     return NACL_SYSCALL (chmod) (pathname, mode);
 }
 
+static int nacl_irt_fchmod (int fd, mode_t mode)
+{
+    return NACL_SYSCALL (fchmod) (fd, mode);
+}
+
 static int nacl_irt_getuid(void) {
     return NACL_SYSCALL (getuid) ();
 }
@@ -1055,6 +1061,7 @@ init_irt_table (void)
   __nacl_irt_mkdir = nacl_irt_mkdir;
   __nacl_irt_chdir = nacl_irt_chdir;
   __nacl_irt_chmod = nacl_irt_chmod;
+  __nacl_irt_fchmod = nacl_irt_fchmod;
   __nacl_irt_rmdir = nacl_irt_rmdir;
   __nacl_irt_getuid = nacl_irt_getuid;
   __nacl_irt_geteuid = nacl_irt_geteuid;
diff --git a/sysdeps/nacl/irt_syscalls.h b/sysdeps/nacl/irt_syscalls.h
index 06c43990..4caf3434 100644
--- a/sysdeps/nacl/irt_syscalls.h
+++ b/sysdeps/nacl/irt_syscalls.h
@@ -43,6 +43,7 @@ extern int (*__nacl_irt_mkdir) (const char* pathname, mode_t mode);
 extern int (*__nacl_irt_rmdir) (const char* pathname);
 extern int (*__nacl_irt_chdir) (const char* pathname);
 extern int (*__nacl_irt_chmod) (const char* pathname, mode_t mode);
+extern int (*__nacl_irt_fchmod) (int fd, mode_t mode);
 
 extern int (*__nacl_irt_getuid) (void);
 extern int (*__nacl_irt_geteuid) (void);
diff --git a/sysdeps/nacl/nacl_syscalls.h b/sysdeps/nacl/nacl_syscalls.h
index a2eab466..ea05c84d 100644
--- a/sysdeps/nacl/nacl_syscalls.h
+++ b/sysdeps/nacl/nacl_syscalls.h
@@ -144,6 +144,7 @@
 #define NACL_sys_rmdir                  132
 #define NACL_sys_statfs                 133
 #define NACL_sys_fstatfs                134
+#define NACL_sys_fchmod                 135
 #define NACL_sys_socket                 136
 #define NACL_sys_getsockopt             137
 #define NACL_sys_setsockopt             138
@@ -205,6 +206,7 @@ typedef int (*TYPE_nacl_getgid) (void);
 typedef int (*TYPE_nacl_getegid) (void);
 typedef int (*TYPE_nacl_chdir) (const char* pathname);
 typedef int (*TYPE_nacl_chmod) (const char* pathname, mode_t mode);
+typedef int (*TYPE_nacl_fchmod) (int fd, mode_t mode);
 typedef int (*TYPE_nacl_mkdir) (const char* pathname, mode_t mode);
 typedef int (*TYPE_nacl_rmdir) (const char* pathname);
 
diff --git a/sysdeps/nacl/sysdep.h b/sysdeps/nacl/sysdep.h
index a5d376a7..43f7adf5 100644
--- a/sysdeps/nacl/sysdep.h
+++ b/sysdeps/nacl/sysdep.h
@@ -329,9 +329,12 @@ INTERNAL_SYSCALL_fchdir_1 (int *err, int fd)
 __extern_always_inline int
 INTERNAL_SYSCALL_fchmod_2 (int *err, int fd, mode_t mode)
 {
-  log_unimplemented("fchmod unimplemented");
-  *err = (38 /* ENOSYS */);
-  return 0;
+  int rv = __nacl_irt_fchmod (fd, mode);
+  if(rv < 0) {
+    *err = -rv;
+    return -1;
+  }
+  return rv;
 }
 
 __extern_always_inline int