An automated positive airway pressure device that monitors respiratory patterns and provides dynamic, real-time, relational pressure has been developed for the treatment of obstructive sleep apnea (OSA). The purpose of this study was to compare self-adjusting pressure to classical nasal continuous positive airway pressure (NCPAP). Subjects were newly diagnosed patients with a minimum respiratory disturbance index (RDI) of 15 episodes per hour who had undergone NCPAP titration and been using classical NCPAP at home on a nightly basis for at least 2 weeks. Patients then underwent repeat standard polysomnographic (PSG) evaluations for 2 nights using a self-adjusting pressure mode and a standard NCPAP mode randomly assigned in a single-blind crossover fashion. Eight males and four females (n = 12), aged 48.4 +/- 12.2 years [mean +/- and standard deviation (SD)], completed the study. During initial diagnostic PSG, the RDI was 57.3 +/- 30.8 episodes per hour. The RDI and minimum oxygen saturation for both treatment nights were significantly improved from those of the diagnostic PSGs (p < 0.001). The subjects spent 63.1 +/- 34.2% of total sleep time below prescribed pressure while on automatic pressure Percent of total sleep time in stage 3/4 sleep was significantly higher during self-adjusting pressure, at 8.6 +/- 7.5%, compared to standard NCPAP, at 4.6 +/- 6.0% (p < 0.05). Computerized adjustable nasal positive airway pressure effectively controls OSA, fluidly providing the minimal pressure necessary to control respiratory events without causing sleep disruption.