The change in the output characteristics of planetary hydraulic machines during operation depends on the stable operation of their elements associated with the displacement of the working fluid - rotors, the service life of which depends on the quality of the manufacture of their toothed profile and is determined by the error of its shape. The issue of increasing the service life of hydraulic motor rotors by changing their design is relevant. As a result of the studies, the design of the internal and external rotors of a planetary hydraulic motor was substantiated and developed, ensuring the stability of the geometric shape of their toothed profiles during manufacture. The use of selective assembly in production will ensure the value of the technological gap required for temperature compensation of rotor expansion within 0.015 mm with a tolerance ± 0.005 mm. The developed mathematical apparatus describes the change in the output parameters of a planetary hydraulic motor under operating conditions, which will allow predicting the change in its technical condition at the design stage. It has been established that the proposed design for manufacturing the toothed surfaces of the planetary hydraulic motor rotors is efficient and technologically feasible, the total manufacturing error of the toothed contour shape does not exceed 0.008 mm, and the maximum value of the diametrical gap is Glim = 0.35 mm, which is more than 2 times higher than this parameter compared to a serial hydraulic motor.