The current study describes the assessment and treatment of the problem behavior of 3 individuals with autism for whom initial functional analysis results were inconclusive. Subsequent analyses revealed that the interruption of free-operant behavior using "do" requests (Study 1) as well as "do" and "don't" requests (Study 2) occasioned problem behavior. Initially, treatment involved differential and noncontingent reinforcement without interruption. To make the intervention more sustainable in the natural environment (where interruptions are unavoidable), a two-component multiple-schedule arrangement was used to progressively increase the period of time in which ongoing activities would be interrupted. During generalization sessions, the intervention was applied across a variety of contexts and therapists.