Three research studies were conducted to investigate the differential effects of externally administered, self-administered and self-determined reinforcement contingencies on the work production rates of developmentally disabled workers. The results of Expt. I indicated that Client 1, a profoundly retarded male, would work at equivalent rates under externally administered or self-administered reinforcers. Experiment II indicated that a severely retarded male would also work at a high work rate under a self-determined reinforcement contingency. The results of Expt. III replicated these findings in a more controlled design. Different tasks adapted from community workshops were utilized in each study. The implications of these studies for developing independent vocational behaviour in the retarded were discussed.