diff --git a/system/core/Log.php b/system/core/Log.php
index b0576c5..ab8ae28 100644
--- a/system/core/Log.php
+++ b/system/core/Log.php
@@ -198,7 +198,12 @@
 			return FALSE;
 		}
 
-		$message .= $level.' - '.date($this->_date_fmt).' --> '.$msg."\n";
+		// Instantiate DateTime with microseconds accuracy to allow proper use of "u" character in date format
+		$t = microtime(true);
+		$micro = sprintf("%06d",($t - floor($t)) * 1000000);
+		$date = new DateTime(date('Y-m-d H:i:s.'.$micro, $t));
+
+		$message .= $level.' - '.$date->format($this->_date_fmt).' --> '.$msg."\n";
 
 		flock($fp, LOCK_EX);
 
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 05442d8..5b2813b 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -553,6 +553,7 @@
 
       -  Added a ``$config['log_file_permissions']`` setting.
       -  Changed the library constructor to try to create the **log_path** directory if it doesn't exist.
+      -  Added support for microseconds ("u" date format character) in ``$config['log_date_format']``
 
    -  Added `compatibility layers <general/compatibility_functions>` for: