diff --git a/src/mzscheme/src/mzrt.c b/src/mzscheme/src/mzrt.c
index 67632fd842..8ef8fc92b5 100644
--- a/src/mzscheme/src/mzrt.c
+++ b/src/mzscheme/src/mzrt.c
@@ -265,6 +265,38 @@ int mzrt_mutex_destroy(mzrt_mutex *mutex) {
   return pthread_mutex_destroy(&mutex->mutex);
 }
 
+struct mzrt_cond {
+  pthread_cond_t cond;
+};
+
+int mzrt_cond_create(mzrt_cond **cond) {
+  *cond = malloc(sizeof(mzrt_cond));
+  return pthread_cond_init(&(*cond)->cond, NULL);
+}
+
+int mzrt_cond_wait(mzrt_cond *cond, mzrt_mutex *mutex) {
+  return pthread_cond_wait(&cond->cond, &mutex->mutex);
+}
+
+int mzrt_cond_timedwait(mzrt_cond *cond, mzrt_mutex *mutex, long seconds, long nanoseconds) {
+  struct timespec timeout;
+  timeout.tv_sec  = seconds;
+  timeout.tv_nsec = nanoseconds;
+  return pthread_cond_timedwait(&cond->cond, &mutex->mutex, &timeout);
+}
+
+int mzrt_cond_signal(mzrt_cond *cond) {
+  return pthread_cond_signal(&cond->cond);
+}
+
+int mzrt_cond_broadcast(mzrt_cond *cond) {
+  return pthread_cond_broadcast(&cond->cond);
+}
+
+int mzrt_cond_destroy(mzrt_cond *cond) {
+  return pthread_cond_destroy(&cond->cond);
+}
+
 
 #ifdef MZ_XFORM
 END_XFORM_SUSPEND;
@@ -410,6 +442,35 @@ int mzrt_mutex_destroy(mzrt_mutex *mutex) {
   return 0;
 }
 
+struct mzrt_cond {
+  pthread_cond_t cond;
+};
+
+int mzrt_cond_create(mzrt_cond **cond) {
+  *cond = malloc(sizeof(mzrt_cond));
+  return pthread_cond_init(&(*cond)->cond, NULL);
+}
+
+int mzrt_cond_wait(mzrt_cond *cond, mzrt_mutex *mutex) {
+  return pthread_cond_wait(&cond->cond, &mutex->mutex);
+}
+
+int mzrt_cond_timedwait(mzrt_cond *cond, mzrt_mutex *mutex) {
+  return pthread_cond_timedwait(&cond->cond, &mutex->mutex);
+}
+
+int mzrt_cond_signal(mzrt_cond *cond) {
+  return pthread_cond_signal(&cond->cond);
+}
+
+int mzrt_cond_broadcast(mzrt_cond *cond) {
+  return pthread_cond_broadcast(&cond->cond);
+}
+
+int mzrt_cond_destroy(mzrt_cond *cond) {
+  return pthread_cond_destroy(&cond->cond);
+}
+
 #ifdef MZ_XFORM
 END_XFORM_SUSPEND;
 #endif
diff --git a/src/mzscheme/src/mzrt.h b/src/mzscheme/src/mzrt.h
index 98c96b864a..9c6754f00e 100644
--- a/src/mzscheme/src/mzrt.h
+++ b/src/mzscheme/src/mzrt.h
@@ -58,6 +58,15 @@ int mzrt_mutex_trylock(mzrt_mutex *mutex);
 int mzrt_mutex_unlock(mzrt_mutex *mutex);
 int mzrt_mutex_destroy(mzrt_mutex *mutex);
 
+/****************** THREAD COND *******************************************/
+typedef struct mzrt_cond mzrt_cond; /* OPAQUE DEFINITION */
+int mzrt_cond_create(mzrt_cond **cond);
+int mzrt_cond_wait(mzrt_cond *cond, mzrt_mutex *mutex);
+int mzrt_cond_timedwait(mzrt_cond *cond, mzrt_mutex *mutex, long seconds, long nanoseconds);
+int mzrt_cond_signal(mzrt_cond *cond);
+int mzrt_cond_broadcast(mzrt_cond *cond);
+int mzrt_cond_destroy(mzrt_cond *cond);
+
 
 #endif