diff --git a/evthread_win32.c b/evthread_win32.c
new file mode 100644
index 0000000..fabd981
--- /dev/null
+++ b/evthread_win32.c
@@ -0,0 +1,339 @@
+/*
+ * Copyright 2009-2012 Niels Provos and Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "event2/event-config.h"
+
+#ifdef WIN32
+#ifndef _WIN32_WINNT
+/* Minimum required for InitializeCriticalSectionAndSpinCount */
+#define _WIN32_WINNT 0x0403
+#endif
+#include <winsock2.h>
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#undef WIN32_LEAN_AND_MEAN
+#include <sys/locking.h>
+#endif
+
+struct event_base;
+#include "event2/thread.h"
+
+#include "mm-internal.h"
+#include "evthread-internal.h"
+
+#define SPIN_COUNT 2000
+
+static void *
+evthread_win32_lock_create(unsigned locktype)
+{
+	CRITICAL_SECTION *lock = mm_malloc(sizeof(CRITICAL_SECTION));
+	if (!lock)
+		return NULL;
+	if (InitializeCriticalSectionAndSpinCount(lock, SPIN_COUNT) == 0) {
+		mm_free(lock);
+		return NULL;
+	}
+	return lock;
+}
+
+static void
+evthread_win32_lock_free(void *_lock, unsigned locktype)
+{
+	CRITICAL_SECTION *lock = _lock;
+	DeleteCriticalSection(lock);
+	mm_free(lock);
+}
+
+static int
+evthread_win32_lock(unsigned mode, void *_lock)
+{
+	CRITICAL_SECTION *lock = _lock;
+	if ((mode & EVTHREAD_TRY)) {
+		return ! TryEnterCriticalSection(lock);
+	} else {
+		EnterCriticalSection(lock);
+		return 0;
+	}
+}
+
+static int
+evthread_win32_unlock(unsigned mode, void *_lock)
+{
+	CRITICAL_SECTION *lock = _lock;
+	LeaveCriticalSection(lock);
+	return 0;
+}
+
+static unsigned long
+evthread_win32_get_id(void)
+{
+	return (unsigned long) GetCurrentThreadId();
+}
+
+#ifdef WIN32_HAVE_CONDITION_VARIABLES
+static void WINAPI (*InitializeConditionVariable_fn)(PCONDITION_VARIABLE)
+	= NULL;
+static BOOL WINAPI (*SleepConditionVariableCS_fn)(
+	PCONDITION_VARIABLE, PCRITICAL_SECTION, DWORD) = NULL;
+static void WINAPI (*WakeAllConditionVariable_fn)(PCONDITION_VARIABLE) = NULL;
+static void WINAPI (*WakeConditionVariable_fn)(PCONDITION_VARIABLE) = NULL;
+
+static int
+evthread_win32_condvar_init(void)
+{
+	HANDLE lib;
+
+	lib = GetModuleHandle(TEXT("kernel32.dll"));
+	if (lib == NULL)
+		return 0;
+
+#define LOAD(name)				\
+	name##_fn = GetProcAddress(lib, #name)
+	LOAD(InitializeConditionVariable);
+	LOAD(SleepConditionVariableCS);
+	LOAD(WakeAllConditionVariable);
+	LOAD(WakeConditionVariable);
+
+	return InitializeConditionVariable_fn && SleepConditionVariableCS_fn &&
+	    WakeAllConditionVariable_fn && WakeConditionVariable_fn;
+}
+
+/* XXXX Even if we can build this, we don't necessarily want to: the functions
+ * in question didn't exist before Vista, so we'd better LoadProc them. */
+static void *
+evthread_win32_condvar_alloc(unsigned condflags)
+{
+	CONDITION_VARIABLE *cond = mm_malloc(sizeof(CONDITION_VARIABLE));
+	if (!cond)
+		return NULL;
+	InitializeConditionVariable_fn(cond);
+	return cond;
+}
+
+static void
+evthread_win32_condvar_free(void *_cond)
+{
+	CONDITION_VARIABLE *cond = _cond;
+	/* There doesn't _seem_ to be a cleaup fn here... */
+	mm_free(cond);
+}
+
+static int
+evthread_win32_condvar_signal(void *_cond, int broadcast)
+{
+	CONDITION_VARIABLE *cond = _cond;
+	if (broadcast)
+		WakeAllConditionVariable_fn(cond);
+	else
+		WakeConditionVariable_fn(cond);
+	return 0;
+}
+
+static int
+evthread_win32_condvar_wait(void *_cond, void *_lock, const struct timeval *tv)
+{
+	CONDITION_VARIABLE *cond = _cond;
+	CRITICAL_SECTION *lock = _lock;
+	DWORD ms, err;
+	BOOL result;
+
+	if (tv)
+		ms = evutil_tv_to_msec(tv);
+	else
+		ms = INFINITE;
+	result = SleepConditionVariableCS_fn(cond, lock, ms);
+	if (result) {
+		if (GetLastError() == WAIT_TIMEOUT)
+			return 1;
+		else
+			return -1;
+	} else {
+		return 0;
+	}
+}
+#endif
+
+struct evthread_win32_cond {
+	HANDLE event;
+
+	CRITICAL_SECTION lock;
+	int n_waiting;
+	int n_to_wake;
+	int generation;
+};
+
+static void *
+evthread_win32_cond_alloc(unsigned flags)
+{
+	struct evthread_win32_cond *cond;
+	if (!(cond = mm_malloc(sizeof(struct evthread_win32_cond))))
+		return NULL;
+	if (InitializeCriticalSectionAndSpinCount(&cond->lock, SPIN_COUNT)==0) {
+		mm_free(cond);
+		return NULL;
+	}
+	if ((cond->event = CreateEvent(NULL,TRUE,FALSE,NULL)) == NULL) {
+		DeleteCriticalSection(&cond->lock);
+		mm_free(cond);
+		return NULL;
+	}
+	cond->n_waiting = cond->n_to_wake = cond->generation = 0;
+	return cond;
+}
+
+static void
+evthread_win32_cond_free(void *_cond)
+{
+	struct evthread_win32_cond *cond = _cond;
+	DeleteCriticalSection(&cond->lock);
+	CloseHandle(cond->event);
+	mm_free(cond);
+}
+
+static int
+evthread_win32_cond_signal(void *_cond, int broadcast)
+{
+	struct evthread_win32_cond *cond = _cond;
+	EnterCriticalSection(&cond->lock);
+	if (broadcast)
+		cond->n_to_wake = cond->n_waiting;
+	else
+		++cond->n_to_wake;
+	cond->generation++;
+	SetEvent(cond->event);
+	LeaveCriticalSection(&cond->lock);
+	return 0;
+}
+
+static int
+evthread_win32_cond_wait(void *_cond, void *_lock, const struct timeval *tv)
+{
+	struct evthread_win32_cond *cond = _cond;
+	CRITICAL_SECTION *lock = _lock;
+	int generation_at_start;
+	int waiting = 1;
+	int result = -1;
+	DWORD ms = INFINITE, ms_orig = INFINITE, startTime, endTime;
+	if (tv)
+		ms_orig = ms = evutil_tv_to_msec(tv);
+
+	EnterCriticalSection(&cond->lock);
+	++cond->n_waiting;
+	generation_at_start = cond->generation;
+	LeaveCriticalSection(&cond->lock);
+
+	LeaveCriticalSection(lock);
+
+	startTime = GetTickCount();
+	do {
+		DWORD res;
+		res = WaitForSingleObject(cond->event, ms);
+		EnterCriticalSection(&cond->lock);
+		if (cond->n_to_wake &&
+		    cond->generation != generation_at_start) {
+			--cond->n_to_wake;
+			--cond->n_waiting;
+			result = 0;
+			waiting = 0;
+			goto out;
+		} else if (res != WAIT_OBJECT_0) {
+			result = (res==WAIT_TIMEOUT) ? 1 : -1;
+			--cond->n_waiting;
+			waiting = 0;
+			goto out;
+		} else if (ms != INFINITE) {
+			endTime = GetTickCount();
+			if (startTime + ms_orig <= endTime) {
+				result = 1; /* Timeout */
+				--cond->n_waiting;
+				waiting = 0;
+				goto out;
+			} else {
+				ms = startTime + ms_orig - endTime;
+			}
+		}
+		/* If we make it here, we are still waiting. */
+		if (cond->n_to_wake == 0) {
+			/* There is nobody else who should wake up; reset
+			 * the event. */
+			ResetEvent(cond->event);
+		}
+	out:
+		LeaveCriticalSection(&cond->lock);
+	} while (waiting);
+
+	EnterCriticalSection(lock);
+
+	EnterCriticalSection(&cond->lock);
+	if (!cond->n_waiting)
+		ResetEvent(cond->event);
+	LeaveCriticalSection(&cond->lock);
+
+	return result;
+}
+
+int
+evthread_use_windows_threads(void)
+{
+	struct evthread_lock_callbacks cbs = {
+		EVTHREAD_LOCK_API_VERSION,
+		EVTHREAD_LOCKTYPE_RECURSIVE,
+		evthread_win32_lock_create,
+		evthread_win32_lock_free,
+		evthread_win32_lock,
+		evthread_win32_unlock
+	};
+
+
+	struct evthread_condition_callbacks cond_cbs = {
+		EVTHREAD_CONDITION_API_VERSION,
+		evthread_win32_cond_alloc,
+		evthread_win32_cond_free,
+		evthread_win32_cond_signal,
+		evthread_win32_cond_wait
+	};
+#ifdef WIN32_HAVE_CONDITION_VARIABLES
+	struct evthread_condition_callbacks condvar_cbs = {
+		EVTHREAD_CONDITION_API_VERSION,
+		evthread_win32_condvar_alloc,
+		evthread_win32_condvar_free,
+		evthread_win32_condvar_signal,
+		evthread_win32_condvar_wait
+	};
+#endif
+
+	evthread_set_lock_callbacks(&cbs);
+	evthread_set_id_callback(evthread_win32_get_id);
+#ifdef WIN32_HAVE_CONDITION_VARIABLES
+	if (evthread_win32_condvar_init()) {
+		evthread_set_condition_callbacks(&condvar_cbs);
+		return 0;
+	}
+#endif
+	evthread_set_condition_callbacks(&cond_cbs);
+
+	return 0;
+}
+