diff --git a/libnmap/process.py b/libnmap/process.py
index 7b79718..48f2084 100644
--- a/libnmap/process.py
+++ b/libnmap/process.py
@@ -260,7 +260,7 @@ def run(self):
 
         while self.__nmap_proc.poll() is None:
             for streamline in iter(self.__nmap_proc.stdout.readline, ''):
-                self.__stdout += streamline
+                self.__stdout += str(streamline)
                 evnt = self.__process_event(streamline)
                 if self.__nmap_event_callback and evnt:
                     self.__nmap_event_callback(self)