diff --git a/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutFilter.java b/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutFilter.java
index 684ce5d..267e73d 100644
--- a/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutFilter.java
+++ b/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutFilter.java
@@ -75,7 +75,11 @@ public final class SingleSignOutFilter extends AbstractConfigurationFilter {
                             log.trace ("Invalidating session [" + sessionID + "] for ST [" + sessionIdentifier + "]");
                         }
                         
-                        session.invalidate();
+                        try {
+                        	session.invalidate();
+                        } catch (final IllegalStateException e) {
+                        	log.debug(e,e);
+                        }
                 	}
                   return;
                 }