diff --git a/src/node.cc b/src/node.cc
index f6ae19da928973..d429a9c7f2899b 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -1296,7 +1296,8 @@ static Handle<Value> CwdForDrive(const Arguments& args) {
   env_key[1] = (WCHAR) drive;
 
   DWORD len = GetEnvironmentVariableW(env_key, NULL, 0);
-  if (len == 0 && GetLastError() == ERROR_ENVVAR_NOT_FOUND) {
+  if (len == 0 && (GetLastError() == ERROR_ENVVAR_NOT_FOUND ||
+      GetLastError() == ERROR_SUCCESS)) {
     // There is no current directory for that drive. Default to drive + ":\".
     Local<String> cwd = String::Concat(String::New(&drive, 1),
                                        String::New(":\\"));
@@ -1317,7 +1318,7 @@ static Handle<Value> CwdForDrive(const Arguments& args) {
   }
 
   DWORD len2 = GetEnvironmentVariableW(env_key, buffer, len);
-  if (len2 == 0 || len2 >= len) {
+  if ((len2 == 0 && GetLastError() != ERROR_SUCCESS) || len2 >= len) {
     // Error
     delete[] buffer;
     Local<Value> exception = Exception::Error(
@@ -1869,12 +1870,28 @@ static void ProcessTitleSetter(Local<String> property,
 
 static Handle<Value> EnvGetter(Local<String> property,
                                const AccessorInfo& info) {
+  HandleScope scope;
+#ifdef __POSIX__
   String::Utf8Value key(property);
   const char* val = getenv(*key);
   if (val) {
-    HandleScope scope;
     return scope.Close(String::New(val));
   }
+#else  // _WIN32
+  String::Value key(property);
+  WCHAR buffer[32767]; // The maximum size allowed for environment variables.
+  DWORD result = GetEnvironmentVariableW(reinterpret_cast<WCHAR*>(*key),
+                                         buffer,
+                                         ARRAY_SIZE(buffer));
+  // If result >= sizeof buffer the buffer was too small. That should never
+  // happen. If result == 0 and result != ERROR_SUCCESS the variable was not
+  // not found.
+  if ((result > 0 || GetLastError() == ERROR_SUCCESS) &&
+      result < ARRAY_SIZE(buffer)) {
+    return scope.Close(String::New(reinterpret_cast<uint16_t*>(buffer), result));
+  }
+#endif
+  // Not found
   return Undefined();
 }
 
@@ -1883,66 +1900,82 @@ static Handle<Value> EnvSetter(Local<String> property,
                                Local<Value> value,
                                const AccessorInfo& info) {
   HandleScope scope;
+#ifdef __POSIX__
   String::Utf8Value key(property);
   String::Utf8Value val(value);
-
-#ifdef __POSIX__
   setenv(*key, *val, 1);
-#else  // __WIN32__
-  int n = key.length() + val.length() + 2;
-  char* pair = new char[n];
-  snprintf(pair, n, "%s=%s", *key, *val);
-  int r = _putenv(pair);
-  if (r) {
-    fprintf(stderr, "error putenv: '%s'\n", pair);
+#else  // _WIN32
+  String::Value key(property);
+  String::Value val(value);
+  WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
+  // Environment variables that start with '=' are read-only.
+  if (key_ptr[0] != L'=') {
+    SetEnvironmentVariableW(key_ptr, reinterpret_cast<WCHAR*>(*val));
   }
-  delete [] pair;
 #endif
-
-  return value;
+  // Whether it worked or not, always return rval.
+  return scope.Close(value);
 }
 
 
 static Handle<Integer> EnvQuery(Local<String> property,
                                 const AccessorInfo& info) {
+  HandleScope scope;
+#ifdef __POSIX__
   String::Utf8Value key(property);
   if (getenv(*key)) {
-    HandleScope scope;
     return scope.Close(Integer::New(None));
   }
-  return Handle<Integer>();
+#else  // _WIN32
+  String::Value key(property);
+  WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
+  if (GetEnvironmentVariableW(key_ptr, NULL, 0) > 0 ||
+      GetLastError() == ERROR_SUCCESS) {
+    if (key_ptr[0] == L'=') {
+      // Environment variables that start with '=' are hidden and read-only.
+      return scope.Close(Integer::New(v8::ReadOnly ||
+                                      v8::DontDelete ||
+                                      v8::DontEnum));
+    } else {
+      return scope.Close(Integer::New(None));
+    }
+  }
+#endif
+  // Not found
+  return scope.Close(Handle<Integer>());
 }
 
 
 static Handle<Boolean> EnvDeleter(Local<String> property,
                                   const AccessorInfo& info) {
   HandleScope scope;
-
-  String::Utf8Value key(property);
-
-  if (getenv(*key)) {
 #ifdef __POSIX__
-    unsetenv(*key);	// prototyped as `void unsetenv(const char*)` on some platforms
+  String::Utf8Value key(property);
+  // prototyped as `void unsetenv(const char*)` on some platforms
+  if (unsetenv(*key) < 0) {
+    // Deletion failed. Return true if the key wasn't there in the first place,
+    // false if it is still there.
+    return scope.Close(Boolean::New(getenv(*key) == NULL));
+  };
 #else
-    int n = key.length() + 2;
-    char* pair = new char[n];
-    snprintf(pair, n, "%s=", *key);
-    int r = _putenv(pair);
-    if (r) {
-      fprintf(stderr, "error unsetenv: '%s'\n", pair);
-    }
-    delete [] pair;
-#endif
-    return True();
+  String::Value key(property);
+  WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
+  if (key_ptr[0] == L'=' || !SetEnvironmentVariableW(key_ptr, NULL)) {
+    // Deletion failed. Return true if the key wasn't there in the first place,
+    // false if it is still there.
+    bool rv = GetEnvironmentVariableW(key_ptr, NULL, NULL) == 0 &&
+              GetLastError() != ERROR_SUCCESS;
+    return scope.Close(Boolean::New(rv));
   }
-
-  return False();
+#endif
+  // It worked
+  return v8::True();
 }
 
 
 static Handle<Array> EnvEnumerator(const AccessorInfo& info) {
   HandleScope scope;
-
+#ifdef __POSIX__
   int size = 0;
   while (environ[size]) size++;
 
@@ -1954,7 +1987,32 @@ static Handle<Array> EnvEnumerator(const AccessorInfo& info) {
     const int length = s ? s - var : strlen(var);
     env->Set(i, String::New(var, length));
   }
-
+#else  // _WIN32
+  WCHAR* environment = GetEnvironmentStringsW();
+  if (environment == NULL) {
+    // This should not happen.
+    return scope.Close(Handle<Array>());
+  }
+  Local<Array> env = Array::New();
+  WCHAR* p = environment;
+  int i = 0;
+  while (*p != NULL) {
+    WCHAR *s;
+    if (*p == L'=') {
+      // If the key starts with '=' it is a hidden environment variable.
+      p += wcslen(p) + 1;
+      continue;
+    } else {
+      s = wcschr(p, L'=');
+    }
+    if (!s) {
+      s = p + wcslen(p);
+    }
+    env->Set(i++, String::New(reinterpret_cast<uint16_t*>(p), s - p));
+    p = s + wcslen(s) + 1;
+  }
+  FreeEnvironmentStringsW(environment);
+#endif
   return scope.Close(env);
 }