A door closer comprising a housing, a member for driving engagement with a door, the member being rotatable relative to the housing in a door opening direction and in a door closing direction, a spring apparatus within the housing providing a resilient bias, the resilient bias being increased by rotation of the member in the door opening direction and a check device for controlling rotation of the member in the door closing direction and hence closure of the door under the action of the spring apparatus, the door closer having a back check comprising a piston member movable in a cylinder from an initial position against resistance of a fluid medium by rotation of the rotatable member in the opening direction.