Abstract: A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate is disclosed. The apparatus includes an optics compartment that contains a patterned surface of the patterning device and an optical element, and a substrate compartment connected to the optics compartment by a connection that is arranged to pass a patterned beam of radiation from the optical element to the substrate. The apparatus also includes a first flush gas inlet arranged to supply a first flush gas into the connection, a second flush gas inlet adjacent to the patterned surface and arranged to supply a second flush gas into the optics compartment and to create a region adjacent the patterned surface in which the second flush gas flows in a direction with a component normal to and away from the patterned surface, and a gas pump arranged to pump the flush gases from the optics compartment.