STUDY DESIGN: A prospective cohort with acute tetraplegia. OBJECTIVES: Obstructive sleep apnoea (OSA) is common within weeks of tetraplegia. This study aimed at determining the feasibility of auto-titrating continuous positive airway pressure (CPAP) to treat OSA after acute tetraplegia. SETTING: The Victorian Spinal Cord Service, Melbourne, Australia. METHODS: Participants underwent full, portable polysomnography. Those with an apnoea hypopnoea index of more than 10 events per hour were defined as having OSA and were offered treatment with CPAP. Treatment adherence was objectively monitored, and measures of quality of life, sleepiness and functional outcomes were determined at enrollment and 3 months later at study conclusion. RESULTS: A total of 44 patients were admitted to our Spinal Cord Service over 9 months, and 19 participated. Fourteen of them had OSA and seven were adherent with therapy for 3 months. Compared with those who did not have OSA, and with those with OSA who were not adherent with CPAP, those who adhered to CPAP were older (mean (s.d.) age 54 years (13) versus non-adherent 28 years (15) and no OSA 29 years (10)) and heavier (body mass index (BMI) 32.5 (11.7), 24.1 (3.7) and 20.6 (3.1), respectively). CPAP-adherant patients and those without OSA showed a 50% or greater improvement in their state sleepiness over the 3 months. Patients with OSA who did not tolerate CPAP had no improvement in sleepiness. CONCLUSION: Auto-titrating CPAP is a feasible treatment for OSA in acute tetraplegia. Intensive clinical support was required initially, and a tolerance of therapy for at least 4 h for one of the first 3 days was predictive of good CPAP usage. SPONSORSHIP: Transport Accident Commission.