Abstract: A lithographic apparatus is disclosed. The apparatus includes an illuminator for conditioning a beam of radiation, and a first support for supporting a patterning device that serves to pattern the beam of radiation according to a desired pattern. The apparatus also includes a second support for supporting a substrate, a projection system for projecting the patterned beam onto a target portion of the substrate, and at least one gas generator for generating a conditioned gas flow. The gas generator includes a guiding element for guiding the gas flow to a lower volume generally located below a lower surface of the projection system and to a volume between the lower surface and the substrate. The guiding element directs the gas flow in a generally downward direction and then in a direction generally parallel to the lower surface.