diff --git a/spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/RoutesEndpoint.java b/spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/RoutesEndpoint.java
index c7bb70d81f..ccb1a44f77 100644
--- a/spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/RoutesEndpoint.java
+++ b/spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/RoutesEndpoint.java
@@ -64,7 +64,7 @@ public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
 	public Map<String, String> invoke() {
 		Map<String, String> map = new LinkedHashMap<>();
 		for (Route route : this.routes.getRoutes()) {
-			map.put(route.getFullPath(), route.getLocation());
+			map.putIfAbsent(route.getFullPath(), route.getLocation());
 		}
 		return map;
 	}
@@ -72,7 +72,7 @@ public Map<String, String> invoke() {
 	Map<String, RouteDetails> invokeRouteDetails() {
 		Map<String, RouteDetails> map = new LinkedHashMap<>();
 		for (Route route : this.routes.getRoutes()) {
-			map.put(route.getFullPath(), new RouteDetails(route));
+			map.putIfAbsent(route.getFullPath(), new RouteDetails(route));
 		}
 		return map;
 	}