This paper reviews the efficacy of auto-titrating continuous positive airway pressure (APAP) for treatment of obstructive sleep apnea. It is based on a review of 30 articles published in peer review journals conducted by a task force appointed by the American Academy of Sleep Medicine to develop practice parameters for use of APAP devices for treatment of obstructive sleep apnea (OSA). The data indicate that APAP can be used to treat many patients with OSA (auto-adjusting) or to identify an effective optimal fixed level of continuous positive airway pressure (CPAP) for treatment (auto-titration). Patients with significant congestive heart failure, chronic obstructive pulmonary disease (COPD), or significant amounts of central apnea were excluded from many treatment trials and there is insufficient evidence that APAP can be used to treat these patients. Many clinical trials have been performed in patients already on CPAP or with the initial APAP night in a laboratory setting. At this time only a few studies have evaluated initial titration with APAP in CPAP-naïve patients in an unattended setting. Further studies of APAP in this circumstance are needed. No studies have systematically compared the efficacy of one APAP technology with another. Devices using different technology may not give the same results in a given patient. Devices solely dependent on vibration may not work in non-snorers or patient who have undergone upper-airway surgery. High mask or mouth leaks may prevent adequate titration in devices monitoring snoring, flow, or impedance (forced oscillation technique). Review of the raw data to identify periods of high leak was performed in several of the APAP titration studies, to identify a pressure for fixed CPAP treatment or to determine if the titration was adequate. There is conflicting evidence for and against the premise that treatment with APAP increases acceptance and adherence compared to fixed CPAP. In studies demonstrating an increase in adherence with APAP, there was similar improvement in measures of daytime sleepiness as with fixed CPAP treatment. Further studies are needed to determine if APAP can increase acceptance or adherence with positive pressure treatment in patients with OSA.