diff --git a/guides/source/debugging_rails_applications.textile b/guides/source/debugging_rails_applications.textile
index 903ed59e7b09bb3d1ddd84fce0108b1ec8ec9509..45fa4ada789ada6463764955d545b4405222ad91 100644
--- a/guides/source/debugging_rails_applications.textile
+++ b/guides/source/debugging_rails_applications.textile
@@ -124,7 +124,7 @@ h4. Log Levels
 
 When something is logged it's printed into the corresponding log if the log level of the message is equal or higher than the configured log level. If you want to know the current log level you can call the +Rails.logger.level+ method.
 
-The available log levels are: +:debug+, +:info+, +:warn+, +:error+, and +:fatal+, corresponding to the log level numbers from 0 up to 4 respectively. To change the default log level, use
+The available log levels are: +:debug+, +:info+, +:warn+, +:error+, +:fatal+, and +:unknown+, corresponding to the log level numbers from 0 up to 5 respectively. To change the default log level, use
 
 <ruby>
 config.log_level = :warn # In any environment initializer, or