An air duct filter apparatus for filtering air discharged from an air duct into a room, vehicle or other space at a duct opening in a surface. The apparatus has a venting device, such as a register or vent, that fits within the duct opening. A pair of filter brackets on the venting device support an air filter behind a venting area, typically having louvers, of the venting device. Preferably, the air filter is sized to frictionally engage the filter brackets so it will be held in place but be easily removable from the brackets. A pair of duct brackets are mounted to the surface on opposite sides of the duct opening. A connecting mechanism connects the venting device with the duct brackets in a manner that allows the venting device to be pulled away from the surface to inspect, clean or replace the air filter without using tools.