diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index 5036289b0..96e59a4c9 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -248,7 +248,8 @@ class YoutubeDL(object):
     source_address:    (Experimental) Client-side IP address to bind to.
     call_home:         Boolean, true iff we are allowed to contact the
                        youtube-dl servers for debugging.
-    sleep_interval:    Number of seconds to sleep before each download.
+    sleep_interval:    A random number of seconds to sleep before each download.
+                       The script will choose a random number below sleep_interval.
     listformats:       Print an overview of available video formats and exit.
     list_thumbnails:   Print a table of all thumbnails and exit.
     match_filter:      A function that gets called with the info_dict of
diff --git a/youtube_dl/downloader/common.py b/youtube_dl/downloader/common.py
index 1dba9f49a..9dcb103b7 100644
--- a/youtube_dl/downloader/common.py
+++ b/youtube_dl/downloader/common.py
@@ -4,6 +4,7 @@ import os
 import re
 import sys
 import time
+import random
 
 from ..compat import compat_os_name
 from ..utils import (
@@ -342,7 +343,7 @@ class FileDownloader(object):
             })
             return True
 
-        sleep_interval = self.params.get('sleep_interval')
+        sleep_interval = random.randrange(self.params.get('sleep_interval'))
         if sleep_interval:
             self.to_screen('[download] Sleeping %s seconds...' % sleep_interval)
             time.sleep(sleep_interval)