Children with autism have significant communication delays. Although some children develop vocalizations through shaping and differential reinforcement, others rarely exhibit vocalizations, and alternative methods are targeted in intervention. However, vocal language often remains a goal for caregivers and clinicians. Thus, strategies to increase frequency of vocalizations are needed. In the present study, the authors examined the effect of extinction of previously acquired signed mands on vocalizations in three children diagnosed with autism. Experiment 1 examined the effects of differential reinforcement of vocalizations and extinction of signed mands combined. In Experiment 1, it was unknown whether the reinforcement of vocalizations alone could have produced the effects; therefore, Experiment 2 isolated the effects of reinforcement and extinction by reinforcing vocalizations in baseline. An increase in rate of vocalizations occurred following the application of extinction of signed mands and differential reinforcement of vocalizations in Experiment 1 and following extinction of signed mands in Experiment 2. (Contains 5 figures.)