An automatic air conditioner condensate drain line clean-out system (1) having a flushing line (6) which is preferably supplied by a home's hot water heater and connected to a condensate drain line (3). A supply valve (10) that supplies the hot water preferably controlled by a timer (11) that allows the system to be activated on a reoccurring basis. A drain valve (13) is located on the condensate drain line subsequent to a point of connection between the flushing line and the condensate drain line to prevent backflow of water from the flushing line into a drain pan (2) of the air conditioning system.