diff --git a/src/bindings/python/PythonSockets.cpp b/src/bindings/python/PythonSockets.cpp
index be82915..cc8e926 100644
--- a/src/bindings/python/PythonSockets.cpp
+++ b/src/bindings/python/PythonSockets.cpp
@@ -28,24 +28,24 @@
 
 int zts_py_setblocking(int fd, int block)
 {
-	int new_flags, flags, err = 0;
+	int new_flags, cur_flags, err = 0;
 
 	Py_BEGIN_ALLOW_THREADS
-  flags = zts_fcntl(fd, F_GETFL, 0);
+  cur_flags = zts_fcntl(fd, F_GETFL, 0);
 
-	if (flags < 0) {
+	if (cur_flags < 0) {
 		err = ZTS_ERR_SOCKET;
     goto done;
 	}
 
-  if (block) {
+  if (!block) {
     new_flags |= ZTS_O_NONBLOCK;
   } else {
     new_flags &= ~ZTS_O_NONBLOCK;
   }
 
-  if (new_flags != flags) {
-	  err = zts_fcntl(fd, F_SETFL, flags);
+  if (new_flags != cur_flags) {
+	  err = zts_fcntl(fd, F_SETFL, new_flags);
   }
 
 done:
diff --git a/src/bindings/python/sockets.py b/src/bindings/python/sockets.py
index 7adc31a..0f5b879 100644
--- a/src/bindings/python/sockets.py
+++ b/src/bindings/python/sockets.py
@@ -435,7 +435,7 @@ class socket:
         """setblocking(flag)
 
         Sets the socket to blocking mode if flag=True, non-blocking if flag=False."""
-        libzt.zts_py_setblocking(self._fd, block)
+        libzt.zts_py_setblocking(self._fd, flag)
 
     def settimeout(self, value):
         """libzt does not support this (yet)"""