This study examined the interactive role of perceived control and preference for control on adherence in a sample of patients with chronic kidney disease. As part of a randomized controlled trial assessing adherence to fluid-intake restrictions, 119 hemodialysis patients completed measures of these constructs; results indicated that patients with high perceived control and high preference for control demonstrated the most favorable adherence. This suggests that patients who believe health-related outcomes are a function of one’s own behaviors—and having the opportunity to exert control over aspects of treatment—may be most adherent to complex regimens in which self-management is key.