Challenging behaviors exhibited by individuals with developmental disabilities often hinder the acquisition of academic, social, and life skills. Functional analysis has been useful for assessing challenging behavior in various settings. The purpose of this study was to implement an operant methodology for recognizing the functional properties of challenging behavior in people with intellectual disabilities. Four adults diagnosed with profound intellectual disability received assessment under several experimental conditions using a functional analysis methodology: social attention as positive reinforcement, negative reinforcement such as the termination of demands, positive tangible reinforcements, absence of social contingencies, and escape from noisy stimuli. Results showed that different types of reinforcement or avoiding contingencies affected the rate of aggression, self-injury, disruption, stereo-typy, or socially offensive behaviors, and functional analysis may potentially be a viable alternative for identifying challenging behaviors.