diff --git a/std/os/index.zig b/std/os/index.zig
index 0a6f598a2..b5e0129da 100644
--- a/std/os/index.zig
+++ b/std/os/index.zig
@@ -130,16 +130,10 @@ pub fn getRandomBytes(buf: []u8) !void {
             try posixRead(fd, buf);
         },
         Os.windows => {
-            var hCryptProv: windows.HCRYPTPROV = undefined;
-            if (windows.CryptAcquireContextA(&hCryptProv, null, null, windows.PROV_RSA_FULL, 0) == 0) {
-                const err = windows.GetLastError();
-                return switch (err) {
-                    else => unexpectedErrorWindows(err),
-                };
-            }
-            defer _ = windows.CryptReleaseContext(hCryptProv, 0);
-
-            if (windows.CryptGenRandom(hCryptProv, @intCast(windows.DWORD, buf.len), buf.ptr) == 0) {
+            // Call RtlGenRandom() instead of CryptGetRandom() on Windows
+            // https://github.com/rust-lang-nursery/rand/issues/111
+            // https://bugzilla.mozilla.org/show_bug.cgi?id=504270
+            if (!windows.RtlGenRandom(buf.ptr, buf.len)) {
                 const err = windows.GetLastError();
                 return switch (err) {
                     else => unexpectedErrorWindows(err),
@@ -159,8 +153,14 @@ pub fn getRandomBytes(buf: []u8) !void {
 }
 
 test "os.getRandomBytes" {
-    var buf: [50]u8 = undefined;
-    try getRandomBytes(buf[0..]);
+    var buf_a: [50]u8 = undefined;
+    var buf_b: [50]u8 = undefined;
+    // Call Twice
+    try getRandomBytes(buf_a[0..]);
+    try getRandomBytes(buf_b[0..]);
+
+    // Check if random (not 100% conclusive)
+    assert( !mem.eql(u8, buf_a, buf_b) );
 }
 
 /// Raises a signal in the current kernel thread, ending its execution.
diff --git a/std/os/windows/advapi32.zig b/std/os/windows/advapi32.zig
index dcb5a636e..64a820a3b 100644
--- a/std/os/windows/advapi32.zig
+++ b/std/os/windows/advapi32.zig
@@ -28,3 +28,8 @@ pub extern "advapi32" stdcallcc fn RegOpenKeyExW(hKey: HKEY, lpSubKey: LPCWSTR,
 
 pub extern "advapi32" stdcallcc fn RegQueryValueExW(hKey: HKEY, lpValueName: LPCWSTR, lpReserved: LPDWORD,
     lpType: LPDWORD, lpData: LPBYTE, lpcbData: LPDWORD,) LSTATUS;
+
+// RtlGenRandom is known as SystemFunction036 under advapi32
+// http://msdn.microsoft.com/en-us/library/windows/desktop/aa387694.aspx */
+pub extern "advapi32" stdcallcc fn SystemFunction036(output: PVOID, length: ULONG_PTR) BOOL;
+pub const RtlGenRandom = SystemFunction036;
diff --git a/std/os/windows/util.zig b/std/os/windows/util.zig
index dda9ce7a8..c9d2c3c3e 100644
--- a/std/os/windows/util.zig
+++ b/std/os/windows/util.zig
@@ -166,7 +166,7 @@ pub fn windowsUnloadDll(hModule: windows.HMODULE) void {
 }
 
 test "InvalidDll" {
-    if (builtin.os != builtin.Os.windows) return;
+    if (builtin.os != builtin.Os.windows) return error.SkipZigTest;
 
     const DllName = "asdf.dll";
     const allocator = std.debug.global_allocator;