Nonuniformity of hollow conical sprays has been determined experimentally for different values of surface roughness of the injection nozzle of swirl atomizers. The discharge coefficient of the atomizers has also been evaluated for the different surface roughnesses. Nonuniformity was found to be enhanced as the surface roughness of the nozzle increased. The extent over which the nonuniformity persisted, however, decreased with increase of the surface roughness. A nonuniformity parameter was defined to characterize the mass flow variations along the circumference of the spray. Sprays having nonuniformity coefficient less than 0.02 were seen to be formed when the thickness of the liquid film in the nozzle exceeded the surface roughness by a factor of about 1000.