diff --git a/src/statusicon.py b/src/statusicon.py
index 7db0eb28a598ec648b6998ceb6fbbfbfdf82f1e4..6548843d75c31a0868e0139e81455109ef361ae0 100644
--- a/src/statusicon.py
+++ b/src/statusicon.py
@@ -118,13 +118,16 @@ class StatusIcon:
     def on_status_icon_size_changed(self, statusicon, size):
         if size > 31:
             self.statusicon_size = '32'
-        elif size > 23: 
+        elif size > 23:
             self.statusicon_size = '24'
         else:
             self.statusicon_size = '16'
         if os.environ.get('KDE_FULL_SESSION') == 'true':
         # detect KDE session. see #5476
             self.statusicon_size = '32'
+        if os.environ.get('MATE_DESKTOP_SESSION_ID'):
+        # detect MATE session.
+            self.statusicon_size = '16'
         self.set_img()
 
     def set_img(self):