diff --git a/src/main/java/oi/thekraken/grok/api/Grok.java b/src/main/java/oi/thekraken/grok/api/Grok.java
index 0d35008..bc559e6 100644
--- a/src/main/java/oi/thekraken/grok/api/Grok.java
+++ b/src/main/java/oi/thekraken/grok/api/Grok.java
@@ -359,6 +359,9 @@ public void compile(String pattern) throws GrokException {
             // Log the exeception
           }
         }
+        if(!grokPatternDefinition.containsKey(group.get("pattern"))){
+        	throw new GrokException("Pattern name " + group.get("pattern") + " unknown!");
+        }
         namedRegexCollection.put("name" + index,
             (group.get("subname") != null ? group.get("subname") : group.get("name")));
         namedRegex =