diff --git a/service/src/main/java/crawlercommons/urlfrontier/service/AbstractFrontierService.java b/service/src/main/java/crawlercommons/urlfrontier/service/AbstractFrontierService.java
index e474688..15492b7 100644
--- a/service/src/main/java/crawlercommons/urlfrontier/service/AbstractFrontierService.java
+++ b/service/src/main/java/crawlercommons/urlfrontier/service/AbstractFrontierService.java
@@ -595,6 +595,12 @@ public void getURLs(GetParams request, StreamObserver<URLInfo> responseObserver)
                 return;
             }
 
+            // already has its fill of URLs in process
+            if (queue.getInProcess(now) >= maxURLsPerQueue) {
+                responseObserver.onCompleted();
+                return;
+            }
+
             int totalSent =
                     sendURLsForQueue(
                             queue, qwc, maxURLsPerQueue, secsUntilRequestable, now, synchStreamObs);