Behavioral momentum theory states that behavioral resistance to change is positively related to reinforcer rate and independent of response rate under most circumstances. We examined behavioral momentum in humans with developmental disabilities. The experimental procedures were implemented as a computer game. Different rates of positive reinforcement were programmed in two alternating components signaled by distinctive cues. For 10 participants who successfully completed testing, resistance to disruption by an alternate source of reinforcement was greater in the component with the higher reinforcer rate, although the magnitude of the difference varied among individuals. These results confirm reinforcer rate effects consistent with behavioral momentum under laboratory conditions and with the largest number of human beings with developmental disabilities studied to date.