Although response interruption and redirection (RIRD) has been shown to be successful in reducing vocal stereotypy, recent reports have suggested that selective serotonin reuptake inhibitors (SSRIs) may also reduce these behaviors. The purpose of the current investigation was to examine the effects of RIRD with and without sertraline on automatically maintained vocal stereotypy of a 4-year-old boy with autism. Results suggested that vocal stereotypy decreased when RIRD was implemented and that sertraline did not affect the participant's vocal stereotypy. (Contains 1 figure.)