Differential reinforcement of alternative behavior (DRA) is used frequently as a treatment for problem behavior. Previous studies on treatment integrity failures during DRA suggest that the intervention is robust, but research has not yet investigated the effects of different types of integrity failures. We examined the effects of two types of integrity failures on DRA, starting with a human operant procedure and extending the results to children with disabilities in a school setting. Human operant results (Experiment 1) showed that conditions involving reinforcement for problem behavior were more detrimental than failing to reinforce appropriate behavior alone, and that condition order affected the results. Experiments 2 and 3 replicated the effects of combined errors and sequence effects during actual treatment implementation. (Contains 1 table and 7 figures.)