diff --git a/nexus-logging-extras/src/main/resources/META-INF/log/logback.properties b/nexus-logging-extras/src/main/resources/META-INF/log/logback.properties
index 973b7c87c8..49c9d8786a 100644
--- a/nexus-logging-extras/src/main/resources/META-INF/log/logback.properties
+++ b/nexus-logging-extras/src/main/resources/META-INF/log/logback.properties
@@ -12,5 +12,5 @@
 #
 
 root.level=INFO
-appender.pattern=%4d{yyyy-MM-dd HH:mm:ss} %-5p [%-15.15t] - %c - %m%n
+appender.pattern=%4d{yyyy-MM-dd HH:mm:ss} %-5p [%-15.15t] %X{userId} %c - %m%n
 appender.file=${nexus.log-config-dir}/../logs/nexus.log
diff --git a/nexus-web-utils/src/main/java/org/sonatype/nexus/web/MdcUserContextFilter.java b/nexus-web-utils/src/main/java/org/sonatype/nexus/web/MdcUserContextFilter.java
new file mode 100644
index 0000000000..17e6303bf7
--- /dev/null
+++ b/nexus-web-utils/src/main/java/org/sonatype/nexus/web/MdcUserContextFilter.java
@@ -0,0 +1,93 @@
+/*
+ * Sonatype Nexus (TM) Open Source Version
+ * Copyright (c) 2007-2012 Sonatype, Inc.
+ * All rights reserved. Includes the third-party code listed at http://links.sonatype.com/products/nexus/oss/attributions.
+ *
+ * This program and the accompanying materials are made available under the terms of the Eclipse Public License Version 1.0,
+ * which accompanies this distribution and is available at http://www.eclipse.org/legal/epl-v10.html.
+ *
+ * Sonatype Nexus (TM) Professional Version is available from Sonatype, Inc. "Sonatype" and "Sonatype Nexus" are trademarks
+ * of Sonatype, Inc. Apache Maven is a trademark of the Apache Software Foundation. M2eclipse is a trademark of the
+ * Eclipse Foundation. All other trademarks are the property of their respective owners.
+ */
+package org.sonatype.nexus.web;
+
+import org.apache.shiro.SecurityUtils;
+import org.apache.shiro.subject.Subject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.MDC;
+
+import javax.inject.Named;
+import javax.inject.Singleton;
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import java.io.IOException;
+
+// NOTE: This would be better integrated as part of the org.sonatype.security.web.guice.SecurityWebFilter ?
+
+/**
+ * Servlet filter to add user context details to the {@link MDC}.
+ *
+ * @since 2.5
+ */
+@Named
+@Singleton
+public class MdcUserContextFilter
+    implements Filter
+{
+    private static final Logger log = LoggerFactory.getLogger(MdcUserContextFilter.class);
+
+    public static final String USER_ID = "userId";
+
+    public static final String UNKNOWN_USER_ID = "<unknown-user>";
+
+    @Override
+    public void init(final FilterConfig config) throws ServletException {
+        // ignore
+    }
+
+    @Override
+    public void destroy() {
+        // ignore
+    }
+
+    @Override
+    public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
+        throws IOException, ServletException
+    {
+        MDC.put(USER_ID, getCurrentUserId());
+
+        try {
+            chain.doFilter(request, response);
+        }
+        finally {
+            MDC.remove(USER_ID);
+        }
+    }
+
+    private String getCurrentUserId() {
+        String userId = UNKNOWN_USER_ID;
+
+        try {
+            Subject subject = SecurityUtils.getSubject();
+            if (subject != null) {
+                Object principal = subject.getPrincipal();
+                if (principal != null) {
+                    userId = principal.toString();
+                }
+            }
+        }
+        catch (Exception e) {
+            log.warn("Unable to determine current user; ignoring", e);
+        }
+
+        log.trace("Current userId: {}", userId);
+
+        return userId;
+    }
+}
diff --git a/plugins/restlet1x/nexus-restlet1x-plugin/src/main/java/org/sonatype/nexus/web/NexusServletModule.java b/plugins/restlet1x/nexus-restlet1x-plugin/src/main/java/org/sonatype/nexus/web/NexusServletModule.java
index d1a638f470..feed528687 100644
--- a/plugins/restlet1x/nexus-restlet1x-plugin/src/main/java/org/sonatype/nexus/web/NexusServletModule.java
+++ b/plugins/restlet1x/nexus-restlet1x-plugin/src/main/java/org/sonatype/nexus/web/NexusServletModule.java
@@ -42,6 +42,7 @@ protected void configureServlets()
 
         filter("/service/local/*").through( SecurityWebFilter.class );
         filter("/content/*").through( SecurityWebFilter.class );
+        filter("/*").through( MdcUserContextFilter.class );
 
         /*
          * Give components contributed by this plugin a low-level ranking (same level as Nexus core) so they are ordered
diff --git a/plugins/siesta/nexus-siesta-plugin/src/main/java/org/sonatype/nexus/plugins/siesta/SiestaModule.java b/plugins/siesta/nexus-siesta-plugin/src/main/java/org/sonatype/nexus/plugins/siesta/SiestaModule.java
index 2feb2814fe..0e4283f498 100644
--- a/plugins/siesta/nexus-siesta-plugin/src/main/java/org/sonatype/nexus/plugins/siesta/SiestaModule.java
+++ b/plugins/siesta/nexus-siesta-plugin/src/main/java/org/sonatype/nexus/plugins/siesta/SiestaModule.java
@@ -16,6 +16,7 @@
 import com.google.inject.servlet.ServletModule;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.sonatype.nexus.web.MdcUserContextFilter;
 import org.sonatype.security.web.guice.SecurityWebFilter;
 import org.sonatype.sisu.siesta.common.Resource;
 import org.sonatype.sisu.siesta.jackson.SiestaJacksonModule;
@@ -82,6 +83,7 @@ protected String pathOf(final Class<Resource> type) {
             protected void configureServlets() {
                 serve(MOUNT_POINT + "/*").with(SiestaServlet.class);
                 filter(MOUNT_POINT + "/*").through(SecurityWebFilter.class);
+                filter(MOUNT_POINT + "/*").through(MdcUserContextFilter.class);
             }
         });
     }