Background and objective: OSA is a common condition associated with cardiovascular (CV) morbidity. It remains underdiagnosed globally in part due to the limited availability and technical requirements of polysomnography (PSG). The aim of this study was to test the accuracy of two simple methods for diagnosing OSA. Methods: Consecutive subjects identified from a community register with high CV risk were invited to complete the Berlin Sleep Questionnaire and undergo simultaneous, home, overnight PSG and ApneaLink device oximetry and nasal pressure recordings. The relative accuracies of the Berlin Questionnaire, oximetry and nasal pressure results in diagnosing PSG-defined moderate-severe OSA were assessed. Results: Of 257 eligible high CV risk subjects enrolled, 190 completed sleep studies and 143 subjects studies were of sufficient quality to include in final analyses. Moderate-severe OSA was confirmed in 43 of subjects. The Berlin Questionnaire had low overall diagnostic accuracy in this population. However, ApneaLink recordings of oximetry and nasal pressure areas had high diagnostic utility with areas under the receiver operating characteristic curves of 0.933 and 0.933, respectively. At optimal diagnostic thresholds, oximetry and nasal pressure measurements had similar sensitivity (84 vs 86 ) and specificity (84 vs 85 ). Technical failure was lower for oximetry than nasal pressure (5.8 vs 18.9 of tests). Conclusions: In patients with high CV risk overnight single-channel oximetry and nasal pressure measurements may provide high diagnostic accuracy and offer an accessible alternative to full PSG.