A rotary milking unit, provided it is designed and planned correctly has advantages over a conventional fixed herringbone unit. Some of these are: a better working environment and a reduced work load on operators; facilities to practise a higher standard of stockmanship; movements of the platform enabling some work elements to be easily automated. The paper emphasizes the careful thought that requires to be given to selecting the correct type and size of unit. Also the mechanical aids that should be incorporated and plans for the collecting and dispersal yards. Efficient milking, good cow management and good labour use can be achieved only if cows board the platform of their own free will in a continuous stream. In order to achieve this it is important that the collecting yard and entry race be planned to a high standard.