diff --git a/devlib/utils/android.py b/devlib/utils/android.py
index 3a978c8..4c9587d 100755
--- a/devlib/utils/android.py
+++ b/devlib/utils/android.py
@@ -789,7 +789,7 @@ class LogcatMonitor(object):
         if outfile:
             self._logfile = open(outfile, 'w')
         else:
-            self._logfile = tempfile.NamedTemporaryFile()
+            self._logfile = tempfile.NamedTemporaryFile(mode='w')
 
         self.target.clear_logcat()