diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index f965b0fd867..3c758ff6e12 100755
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -66,6 +66,19 @@ def readline(self, length = None):
 		self.pos = self.fp.tell()
 		return data
 
+        def readlines(self, sizehint = -1):
+		lines = []
+		while 1:
+			line = self.readline()
+			if not line:
+				break
+			lines.append(line)
+			if sizehint >= 0:
+				sizehint = sizehint - len(line)
+				if sizehint <= 0:
+					break
+		return lines
+
 	def tell(self):
 		return self.pos - self.start