Gael Lalire created LOGBACK-1351: ------------------------------------ Summary: MDC issue Key: LOGBACK-1351 URL: https://jira.qos.ch/browse/LOGBACK-1351 Project: logback Issue Type: Bug Components: logback-classic Reporter: Gael Lalire Assignee: Logback dev list After -LOGBACK-620-, the MDC map is no longer in InheritableThreadLocal. So when you MDC.put on a thread if you create a new thread from it, the new thread will not receive the value. I think the -LOGBACK-620- was about not copying the map on each thread creation but only when it the map is modified, but the lost of inherited value was unexpected. If so replacing {code:java} final ThreadLocal<Map<String, String>> copyOnThreadLocal = new ThreadLocal<Map<String, String>>();{code} by  {code:java} final ThreadLocal<Map<String, String>> copyOnThreadLocal = new InheritableThreadLocal<Map<String, String>>();{code} will do the fix -- This message was sent by Atlassian JIRA (v7.3.1#73012)