Abstract: An process and apparatus for carrying out the ultrasonic cleaning of a printing cylinder including a cleaning tank, which contains a liquid cleaning detergent into which the printing cylinder to be cleaned is immersed. Heaters are also included for heating and maintaining the temperature of the cleaning liquid at a temperature below 185.degree. F., preferably within the range of 130.degree.-160.degree. F. while the printing cylinder is cleaned. The cleaning of the printing cylinder within the cleaning tank of the apparatus is carried out by ultrasonic waves which are generated and radiated throughout the cleaning liquid for a period of time, generally, between 5-30 minutes. In a preferred embodiment of the apparatus and process, the printing cylinder is continually rotated within the cleaning tank during the period of time when the ultrasonic waves are radiating through the cleaning liquid.