diff --git a/core/src/main/java/org/acegisecurity/util/FilterToBeanProxy.java b/core/src/main/java/org/acegisecurity/util/FilterToBeanProxy.java
index 6c427cdbbb..407516e07b 100644
--- a/core/src/main/java/org/acegisecurity/util/FilterToBeanProxy.java
+++ b/core/src/main/java/org/acegisecurity/util/FilterToBeanProxy.java
@@ -150,7 +150,12 @@ public class FilterToBeanProxy implements Filter {
             .getServletContext());
     }
 
-    private void doInit() throws ServletException {
+    private synchronized void doInit() throws ServletException {
+        if (initialized) {
+            // already initialized, so don't re-initialize
+            return;
+        }
+
         initialized = true;
 
         String targetBean = filterConfig.getInitParameter("targetBean");
diff --git a/doc/xdocs/changes.xml b/doc/xdocs/changes.xml
index cb1e1b0fdd..09e11f5438 100644
--- a/doc/xdocs/changes.xml
+++ b/doc/xdocs/changes.xml
@@ -36,6 +36,7 @@
       <action dev="benalex" type="fix">AbstractAuthenticationToken.getName() now returns username alone if UserDetails present</action>
       <action dev="raykrueger" type="update">AuthorityGranter.grant now returns a java.util.Set of role names, instead of a single role name</action>  
       <action dev="benalex" type="update">JavaDoc improvements</action>  
+      <action dev="benalex" type="fix">Correct synchronization issue with FilterToBeanProxy initialization</action>        
     </release>
     <release version="0.8.2" date="2005-04-20">
       <action dev="benalex" type="fix">Correct location of AuthenticationSimpleHttpInvokerRequestExecutor in clientContext.xml</action>