diff --git a/src/lib/stream.rs b/src/lib/stream.rs
index 157846c76..39360f7c6 100644
--- a/src/lib/stream.rs
+++ b/src/lib/stream.rs
@@ -1016,6 +1016,12 @@ impl<'a> CodedOutputStream<'a> {
     }
 }
 
+impl<'a> Drop for CodedOutputStream<'a> {
+    fn drop(&mut self) {
+        self.flush().unwrap();
+    }
+}
+
 
 #[cfg(test)]
 mod test {
@@ -1263,4 +1269,14 @@ mod test {
             os.write_raw_little_endian64(0xf807a6b5c4d3e2f1)
         });
     }
+
+    #[test]
+    fn test_drop_output_stream_flushes() {
+        let mut v = Vec::new();
+        {
+            let mut os = CodedOutputStream::new(&mut v as &mut Write);
+            os.write_int32_no_tag(1).unwrap();
+        }
+        assert!(v.len() == 1);
+    }
 }