Objective Obstructive sleep apnoea (OSA) is reported to be highly prevalent among Aboriginal Australians. However, no studies have assessed the implementation and efficacy of Continuous Positive Airway Pressure (CPAP) therapy in this population. Hence, we compared the clinical, self-reported perception of sleep quality and polysomnographic (PSG) characteristics among Aboriginal patients with OSA. Methods Adult Aboriginal Australians who underwent both diagnostic (Type 1 & 2) and in-lab CPAP implementation studies between were included. Results Total of 149 patients were identified (46% female, median age 49 years, BMI 35 kg/m 2). The OSA severity was 6% mild, 26% moderate & 68% severe on the diagnostic PSG. On application of CPAP there were significant improvements in; Total Arousal Index (diagnostic 29 to 17/hour on CPAP), Total Apnoea Hypopnea Index (AHI) (diagnostic 48 to 9/hour on CPAP), Non-rapid eye movement (NREM) AHI (diagnostic 47 to 8/hour on CPAP), Rapid eye movement (REM) AHI (diagnostic 56 to 8/hour on CPAP) and oxygen saturation (SpO2) nadir (diagnostic 77% to 85% on CPAP) (p<0.001 for each). Following a single night of CPAP, 54% of patients reported sleeping “better than normal” compared to 12% following the diagnostic study (p=0.003). In multivariate regression models, males had a significantly lesser change in REM AHI than females (5.7 events/hr less change (IQR 0.4, 11.1), p=0.029). Conclusion There is substantial improvement in several sleep related domains on application of CPAP among Aboriginal patients with a good initial acceptance of treatment. Whether the positive impact observed in this study translates to better sleep health outcomes with long-term adherence to CPAP therapy is yet to be assessed.