diff --git a/src/mzscheme/src/mzrt.c b/src/mzscheme/src/mzrt.c
index 8832082806..730186d5ed 100644
--- a/src/mzscheme/src/mzrt.c
+++ b/src/mzscheme/src/mzrt.c
@@ -240,6 +240,32 @@ int mzrt_rwlock_destroy(mzrt_rwlock *lock) {
   return pthread_rwlock_destroy(&lock->lock);
 }
 
+struct mzrt_mutex {
+  pthread_mutex_t mutex;
+};
+
+int mzrt_mutex_create(mzrt_mutex **mutex) {
+  *mutex = malloc(sizeof(mzrt_mutex));
+  return pthread_mutex_init(&(*mutex)->mutex, NULL);
+}
+
+int mzrt_mutex_lock(mzrt_mutex *mutex) {
+  return pthread_mutex_lock(&mutex->mutex);
+}
+
+int mzrt_mutex_trylock(mzrt_mutex *mutex) {
+  return pthread_mutex_trylock(&mutex->mutex);
+}
+
+int mzrt_mutex_unlock(mzrt_mutex *mutex) {
+  return pthread_mutex_unlock(&mutex->mutex);
+}
+
+int mzrt_mutex_destroy(mzrt_mutex *mutex) {
+  return pthread_mutex_destroy(&mutex->mutex);
+}
+
+
 #ifdef MZ_XFORM
 END_XFORM_SUSPEND;
 #endif
@@ -353,6 +379,37 @@ int mzrt_rwlock_destroy(mzrt_rwlock *lock) {
   return rc; 
 }
 
+struct mzrt_mutex {
+  CRITICAL_SECTION critical_section;
+};
+
+int mzrt_mutex_create(mzrt_mutex **mutex) {
+  *mutex = malloc(sizeof(mzrt_mutex));
+  InitializeCriticalSection(&(*mutex)->critical_section);
+  return 0;
+}
+
+int mzrt_mutex_lock(mzrt_mutex *mutex) {
+  EnterCriticalSection(&(*mutex)->critical_section);
+  return 0;
+}
+
+int mzrt_mutex_trylock(mzrt_mutex *mutex) {
+  if (!TryEnterCriticalSection(&(*mutex)->critical_section))
+    return 1;
+  return 0;
+}
+
+int mzrt_mutex_unlock(mzrt_mutex *mutex) {
+  LeaveCriticalSection(&(*mutex)->critical_section);
+  return 0;
+}
+
+int mzrt_mutex_destroy(mzrt_mutex *mutex) {
+  DeleteCriticalSection(&(*mutex)->critical_section);
+  return 0;
+}
+
 #ifdef MZ_XFORM
 END_XFORM_SUSPEND;
 #endif
diff --git a/src/mzscheme/src/mzrt.h b/src/mzscheme/src/mzrt.h
index a5de9a1917..98c96b864a 100644
--- a/src/mzscheme/src/mzrt.h
+++ b/src/mzscheme/src/mzrt.h
@@ -36,6 +36,8 @@ void *mz_proc_thread_wait(mz_proc_thread *thread);
 
 void mzrt_sleep(int seconds);
 
+int mz_proc_thread_self();
+int mz_proc_thread_id(mz_proc_thread* thread);
 
 /****************** THREAD RWLOCK ******************************************/
 /* mzrt_rwlock_*.c */
@@ -48,6 +50,14 @@ int mzrt_rwlock_trywrlock(mzrt_rwlock *lock);
 int mzrt_rwlock_unlock(mzrt_rwlock *lock);
 int mzrt_rwlock_destroy(mzrt_rwlock *lock);
 
+/****************** THREAD MUTEX ******************************************/
+typedef struct mzrt_mutex mzrt_mutex; /* OPAQUE DEFINITION */
+int mzrt_mutex_create(mzrt_mutex **mutex);
+int mzrt_mutex_lock(mzrt_mutex *mutex);
+int mzrt_mutex_trylock(mzrt_mutex *mutex);
+int mzrt_mutex_unlock(mzrt_mutex *mutex);
+int mzrt_mutex_destroy(mzrt_mutex *mutex);
+
 
 #endif