diff --git a/include/errno.h b/include/errno.h
index e82a39b..691236a 100644
--- a/include/errno.h
+++ b/include/errno.h
@@ -17,6 +17,7 @@
 #define EALREADY	0x1BAD000D
 #define EINPROGRESS	0x1BAD000E
 #define ENFILE		0x1BAD000F
+#define ETIMEDOUT	0x1BAD0010
 
 #define EAFNOSUPPORT	0x1BAD0020
 #define ENOPROTOOPT	0x1BAD0021
diff --git a/include/pthread.h b/include/pthread.h
index 59e9825..0fe8afb 100644
--- a/include/pthread.h
+++ b/include/pthread.h
@@ -2,6 +2,8 @@
 #ifndef __PTHREAD_H__
 #define __PTHREAD_H__
 
+#include <time.h>
+
 #define PTHREAD_MUTEX_INITIALIZER	NULL
 #define PTHREAD_COND_INITIALIZER	NULL
 
@@ -53,6 +55,8 @@ int pthread_mutex_unlock(pthread_mutex_t *mutex);
 int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr);
 int pthread_cond_destroy(pthread_cond_t *cond);
 int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex);
+int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+			   const struct timespec *abstime);
 int pthread_cond_signal(pthread_cond_t *cond);
 int pthread_cond_broadcast(pthread_cond_t *cond);
 
diff --git a/include/time.h b/include/time.h
index ca79696..8491da0 100644
--- a/include/time.h
+++ b/include/time.h
@@ -2,6 +2,8 @@
 #ifndef __TIME_H__
 #define __TIME_H__
 
+#include <sys/timespec.h>
+
 struct tm {
     int		tm_sec;
     int		tm_min;
diff --git a/lib/libc/posix/pthread.c b/lib/libc/posix/pthread.c
index 82a575d..af2eac8 100644
--- a/lib/libc/posix/pthread.c
+++ b/lib/libc/posix/pthread.c
@@ -373,6 +373,40 @@ pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
     return 0;
 }
 
+int
+pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+		       const struct timespec *abstime)
+{
+    struct pthread_cond *cnd;
+    uint64_t level;
+
+    if (*cond == NULL) {
+	int status = pthread_cond_init(cond, NULL);
+	if (status != 0)
+	    return status;
+    }
+    cnd = *cond;
+
+    if (mutex)
+	pthread_mutex_unlock(mutex);
+
+    CoreMutex_Lock(&cnd->mtx);
+    level = cnd->enter;
+    cnd->enter++;
+    CoreMutex_Unlock(&cnd->mtx);
+
+    while (level >= cnd->exit) {
+	OSThreadSleep(0);
+
+	// XXX: check time
+    }
+
+    if (mutex)
+	pthread_mutex_lock(mutex);
+
+    return 0;
+}
+
 
 int
 pthread_cond_signal(pthread_cond_t *cond)
diff --git a/sys/include/timespec.h b/sys/include/timespec.h
new file mode 100644
index 0000000..c02110b
--- /dev/null
+++ b/sys/include/timespec.h
@@ -0,0 +1,13 @@
+
+#ifndef __SYS_TIMESPEC_H__
+#define __SYS_TIMESPEC_H__
+
+#include <sys/types.h>
+
+struct timespec {
+    time_t	tv_sec;
+    long	tv_nsec;
+};
+
+#endif /* __SYS_TIMESPEC_H__ */
+