A four-phase study was conducted in the homes of 4 young children who displayed aberrant behavior. Phases 1 and 2 consisted of a series of descriptive and experimental analyses to identify the environmental antecedents and consequences that controlled aberrant behavior. Phases 3 and 4 evaluated the short- and long-term effects of treatment on aberrant behavior, target mands, and collateral (social and toy play) behaviors. The effects of treatment were monitored for up to 27 months to assess long-term suppression of aberrant behavior. The assessment results successfully identified environmental events that occasioned and maintained aberrant behavior for all children. The short-term treatment resulted in immediate decreases in aberrant behavior for 3 of 4 children. Long-term treatment was successful for all children and was correlated with substantial response generalization. These results are interpreted in relation to functional equivalence, pivotal responding, and response generalization.