This research compared the effects of several factors on sustained attention in four participants with mild or mild-to-moderate intellectual disabilities. In each session, each participant received an extended number of conditional discriminations that required a differential response to infrequently occurring target stimuli. We assessed sustained attention across conditions as a function of instructions, response feedback, and accuracy-dependent money delivery. Instructions alone did not maintain high levels of sustained attention in the absence of response feedback and accuracy-dependent money delivery for any of the participants, and the effects of response feedback without accuracy-dependent money delivery were mixed. Accuracy-dependent money delivery reliably engendered high levels of sustained attention for each participant, both with and without response feedback. This research provides procedures for studying sustained attention in individuals with intellectual disabilities for extended periods of time. Such procedures are necessary to investigate the effects of other variables that impact sustained attention in this population. (Contains 1 table and 1 figure.)