The paper presents the history of the development of automatic milking systems and their classification. The objects of study were automatic milking systems that are used in world practice. The analysis of automatic milking systems showed that they have technological and design differences. Technological and design features of automatic milking systems such as "Astronaut A4", "VMS", "M2erlin", "MR-S2", "MR-D2", "RDS FutureLine", "Galaxy Starline" and "Mlone" were considered in working out of this classification. The studies have shown that the existing automatic milking systems differ in the number of milking boxes and their location, type of robot arm, drive control of robot arm, robot arm location, decision of cleaning the teats and stimulating milk flow, decision of entry and exit of cows from the milking boxes.