Six profoundly mentally retarded subjects were taught two tasks of comparable difficulty using different prompting procedures: an antecedent procedure, where the trainer prompted the learner prior to the subject's response and gradually faded the prompt on subsequent trials, approximating an errorless learning model, and a consequent procedure, where the trainer prompted the learner after an error response and gradually faded the prompt on subsequent corrections. Results show that greater gains were made with the antecedent prompting procedure compared to the consequent prompting procedure.