Background There is paucity of information on obstructive sleep apnoea (OSA) and cardiac diseases among Aboriginal Australian patients. This study evaluates the association of various cardiac disease profiles among Aboriginal patients undergoing a diagnostic polysomnography (PSG). Method In this 5-year retrospective study demographics, clinical characteristics, medical and cardiac -conditions were analysed. Results There were total of 340 eligible patients included in the study. The median age was 47 (38–57) years, 51% were males and obesity was noted in 78%. In the overall study participants, cardiac diseases were present in 46%: coronary artery disease (CAD) in 27%, pulmonary hypertension (PH) 19% and atrial fibrillation (AF) 14%. Diabetes and hypertension were noted in 42 and 41% of patients. Overall, 73/340 (21.5%) had two, 69/340 (20.3%) three, 55/340 (16.2%) four, 40/340 (11.8%) five and 10/340 (2.9%) had six comorbidities. In the overall study participants, 297/340 (87%) had OSA (AHI>5/hour). Co- occurrence of OSA and cardiac diseases was found in 140/297 (47%), CAD being the commonest (27%). Patients with OSA had higher number of comorbidities compared to patients without sleep apnoea. Hospital admissions frequency showed a median 2 (IQR: 0-4) times readmission rates since the diagnosis of OSA overall compliance with CPAP therapy was observed in 63 (43%). Conclusion Our study demonstrated that a significant proportion of Aboriginal patients with OSA have co-existing cardiac diseases, with CAD being the commonest. Patients with OSA had a higher number of comorbidities compared to patients without sleep apnoea. Furthermore, hospital admission frequency increased among OSA patients with multiple comorbidities.