diff --git a/src/threadpool.c b/src/threadpool.c
index debaf5ca..dd0abd9a 100644
--- a/src/threadpool.c
+++ b/src/threadpool.c
@@ -101,9 +101,12 @@ static void worker(void* arg) {
 
 
 static void post(QUEUE* q) {
+  int empty_queue;
   uv_mutex_lock(&mutex);
+  empty_queue = QUEUE_EMPTY(&wq);
   QUEUE_INSERT_TAIL(&wq, q);
-  uv_cond_signal(&cond);
+  if (empty_queue)
+    uv_cond_signal(&cond);
   uv_mutex_unlock(&mutex);
 }