We combined functional analyses and concurrent-schedule assessments to identify reinforcer preference during situations in which problem behavior may have been multiply controlled. Participants were 3 children with developmental delays who engaged in problem behavior during toy play with another child and one adult present, suggesting that problem behavior may have been maintained by adult attention or access to tangible reinforcement. Thus, conditions were designed to test attention and access-to-toys hypotheses. Initial functional analyses suggested multiple control. Subsequent concurrent-schedule assessments identified preference between the reinforcers, and treatments were based on these findings. Findings are discussed regarding the assessment of potentially multiply controlled problem behavior.