Structural characteristics of slot machines, such as color, have been implicated in the maintenance of problem gambling. Behavior-analytic research has demonstrated that preferences for identically programmed, concurrently available simulated slot machines can be brought under contextual control, which may provide a functional account of the control exerted by structural characteristics. Specifically, when participants were trained that the color yellow was a contextual cue for ‘more than’ and the color blue was a contextual cue for ‘less than’, participants showed an increased preference for the yellow slot machine, despite both machines being identical in schedule and magnitude of reinforcement. The present experiments sought to replicate and extend these findings in several ways. First, we sought to overcome limitations of pretest/posttest designs by employing a nonconcurrent multiple baseline design, counterbalancing the contextual cues, and employing problem gamblers as participants. Experiments 1 and 2 found that slot machine preferences could be altered in accordance with contextual cues in problem gamblers, and Experiment 3 reported that these preferences could be reversed. All three experiments found that extended exposure to the payout contingencies of a slot machine may weaken the control exerted by the contextual cues.