A power split hybrid wheel drive system of the present invention comprises a planetary gear train (16) coupled to the output shaft of a driving engine (12). A primary motor or generator (18) is coupled to an output shaft of the planetary gear train (16) for receiving power therefrom, and a secondary motor or generator (30, 32) is associated with each driven vehicle wheel (14) to provide an electrical power pathway. A mechanical differential gear train (20) is coupled between the output shaft of the planetary gear train (16) and each driven vehicle wheel; (14) to provide a mechanical power pathway, while a mechanical clutch (22) and brake system (24) is configured to regulate the mechanical power routed to the differential gear train (20). A control system (48) is included to regulate the flow of electrical power between the primary motor (18) and secondary motors or generators (30, 32).