diff --git a/scrapy/utils/log.py b/scrapy/utils/log.py
index a28002c08..51f303216 100644
--- a/scrapy/utils/log.py
+++ b/scrapy/utils/log.py
@@ -146,7 +146,8 @@ class StreamLogger(object):
             self.logger.log(self.log_level, line.rstrip())
 
     def flush(self):
-        pass
+        for h in self.logger.handlers:
+            h.flush()
 
 
 class LogCounterHandler(logging.Handler):