Abstract: A three-stage compressor wherein the housing proper has a central bore with two adjacent bores that are co-axial therewith. A first piston is cooperative with the central bore to define a first stage compression chamber. A second piston smaller than the first piston but integral therewith is received by one of the adjacent bores to define a second stage compression chamber that receives its pressurized air from the first chamber. A third piston smaller than the second piston is received by the remaining one of the adjacent bores to define a third stage compression chamber that receives its pressurized air from the second chamber for further compression.