Background: The most frequently diagnosed sleep disorder among older Veterans is obstructive sleep apnea (OSA), which is associated with serious adverse effects on health, quality of life and survival. Positive airway pressure (PAP) is recommended as first-line treatment (particularly for moderate to severe OSA), but sustained use is difficult to achieve, including among older Veterans, and nearly half of patients with OSA who begin PAP therapy discontinue use within a year. Significance/Impact: Although OSA is a chronic condition, research to date has primarily focused on increasing initial PAP use in patients with newly diagnosed OSA. In addition, most research has not addressed PAP use in older adults, which is unfortunate given the high prevalence and important adverse effects of OSA on their health and well-being. Prior work suggests that behavioral interventions are effective in improving initial PAP use, but little is known of how to address insufficient use over time. Innovation: To address this problem, we developed and pilot-tested a structured, manual-based approach to address insufficient PAP use among older adults with previously diagnosed OSA. The intervention (5 sessions over 8 weeks, then monthly contact for up to 6 months) is designed so it can be provided by individuals (“sleep coaches”) from various disciplines (supervised remotely by a psychologist) in a variety of settings for maximal implementation. Core components of the intervention include: 1) educational and behavioral approaches to improve PAP use, 2) individualized self-management and troubleshooting techniques to address factors contributing to insufficient PAP use, and 3) ongoing review of objective PAP use (via remote monitoring). Specific Aims: Primary Aim 1 will test the efficacy of this intervention for improving PAP usage among older Veterans with previously diagnosed OSA who have insufficient PAP use. Our hypotheses are that the intervention will increase objectively measured PAP