Although of proven health benefit to persons with obstructive sleep apnea (OSA), adherence to continuous positive airway pressure (CPAP) therapy is suboptimal, with patterns of use that are established early and that are not easily altered after the initial experience. In a randomized controlled trial, 70 participants with OSA and cardiovascular disease were assigned to receive either positively or negatively framed education about CPAP. Objective adherence was measured following 30 days of home CPAP therapy. Daytime sleepiness, dispositional optimism, self-efficacy, and depression were also evaluated at baseline and after 30 days. CPAP use was greater in the group receiving negative message framing (p = .015).