diff --git a/src/unisync/synchroniser.py b/src/unisync/synchroniser.py
index 138d356..6f3e911 100644
--- a/src/unisync/synchroniser.py
+++ b/src/unisync/synchroniser.py
@@ -123,15 +123,15 @@ class Synchroniser:
                 f"{self.remote_user}@{self.remote_ip}",
                 "-p", str(self.remote_port)
                 ]
-        master_ssh = subprocess.Popen(command)
-        # TODO: Raise an exception instead of changing the return value
-        try:
-            ret_code = master_ssh.wait(timeout=connection_timeout)
-        except subprocess.TimeoutExpired as e:
-            print("Time to login expired", file=sys.stderr)
-            raise e
-        except KeyboardInterrupt as e:
-            raise e
+        with subprocess.Popen(command) as master_ssh:
+            # TODO: Raise an exception instead of changing the return value
+            try:
+                ret_code = master_ssh.wait(timeout=connection_timeout)
+            except subprocess.TimeoutExpired as e:
+                print("Time to login expired", file=sys.stderr)
+                raise e
+            except KeyboardInterrupt as e:
+                raise e
 
         if ret_code != 0:
             print("Login to remote failed", file=sys.stderr)
@@ -151,8 +151,10 @@ class Synchroniser:
                 f"{self.remote_user}@{self.remote_ip}",
                 "-p", str(self.remote_port)
                 ]
-        close = subprocess.Popen(command)
-        return close.wait()
+        with subprocess.Popen(command) as close:
+            retval = close.wait()
+
+        return retval
 
     def sync_files(self, paths:list, force:bool=False) -> None:
         """Synchronises the files.
@@ -254,8 +256,10 @@ class Synchroniser:
         for arg in other:
             command.append(arg)
 
-        proc = subprocess.Popen(command)
-        ret_code = proc.wait()
+        with subprocess.Popen(command) as proc:
+            ret_code = proc.wait()
+
+        # See unison manual section 6.11
         if ret_code == 3:
             raise FatalSyncError("Synchronisation could not be completed")