diff --git a/safeeyes/SafeEyesCore.py b/safeeyes/SafeEyesCore.py
index 0e2a189..6edf832 100644
--- a/safeeyes/SafeEyesCore.py
+++ b/safeeyes/SafeEyesCore.py
@@ -65,7 +65,8 @@ class SafeEyesCore:
 		self.skip_break_window_classes = [x.lower() for x in config['active_window_class']['skip_break']]
 		self.take_break_window_classes = [x.lower() for x in config['active_window_class']['take_break']]
 		self.custom_exercises = config['custom_exercises']
-		self.time_to_screen_lock = config.get('time_to_screen_lock', -1) 
+		self.time_to_screen_lock = config.get('time_to_screen_lock', -1)
+		self.enable_screen_lock = config.get('enable_screen_lock', False)
 
 		exercises = language['exercises']
 		for short_break_config in config['short_breaks']:
@@ -292,6 +293,10 @@ class SafeEyesCore:
 				audible_alert = self.short_break_exercises[self.short_break_message_index][2]
 				image = self.short_break_exercises[self.short_break_message_index][3]
 			
+
+			if (Utility.is_desktop_lock_supported() and self.enable_screen_lock and self.time_to_screen_lock < seconds):
+				Utility.lock_desktop()
+
 			# Show the break screen
 			self.start_break(message, image)		
 
diff --git a/safeeyes/SettingsDialog.py b/safeeyes/SettingsDialog.py
index 7b1fd1f..2cd26b2 100644
--- a/safeeyes/SettingsDialog.py
+++ b/safeeyes/SettingsDialog.py
@@ -73,7 +73,7 @@ class SettingsDialog:
 		self.switch_strict_break.set_active(config['strict_break'])
 		self.switch_audible_alert.set_active(config['audible_alert'])
 		self.switch_screen_lock.set_sensitive(Utility.is_desktop_lock_supported())
-		self.switch_screen_lock.set_active(Utility.is_desktop_lock_supported() and self.config.get('enable_screen_lock', True))
+		self.switch_screen_lock.set_active(Utility.is_desktop_lock_supported() and self.config.get('enable_screen_lock', False))
 		self.spin_time_to_screen_lock.set_value(self.config.get('time_to_screen_lock', 20))
 		self.on_switch_screen_lock_activate(self.switch_screen_lock, self.switch_screen_lock.get_active())
 
diff --git a/safeeyes/Utility.py b/safeeyes/Utility.py
index 4ad658c..6b88766 100644
--- a/safeeyes/Utility.py
+++ b/safeeyes/Utility.py
@@ -256,3 +256,5 @@ def desktop_envinroment():
 def is_desktop_lock_supported():
 	return desktop_envinroment() in ['unity', 'gnome']
 
+def lock_desktop(): 
+	os.system("gnome-screensaver-command --lock")