One of the basic principles of applied behavior analysis is that behavior change is largely due to that behavior being reinforced. Therefore the use of positive reinforcement is a key component of most behavioral programs for individuals diagnosed with autism. In this study we compared four different classes of reinforcers (i.e., food, praise, toys, and feedback) on the rate of skill acquisition for three individuals diagnosed with autistic disorder. Using a parallel treatments design, the results of this study showed that all four classes of reinforcement were effective for teaching all of the participants. Results also indicated that food reinforecers were more efficient and more preferred. Finally, participants performance during teaching was idiosyncratic across the three participants.