Résumé : Study Objectives: To assess the diagnostic performance of a nonintrusive device placed under the mattress to detect sleep apnea syndrome. Methods: One hundred eighteen patients suspected to have obstructive sleep apnea syndrome completed a night at a sleep clinic with a simultaneous polysomnography (PSG) and recording with the Withings Sleep Analyzers. PSG nights were scored twice: First as simple polygraphy, then as PSG. Results: Average (standard deviation) apnea-hypopnea index from PSG was 31.2 events/h (25.0) and 32.8 events/h (29.9) according to the Withings Sleep Analyzers. The mean absolute error was 9.5 events/h. The sensitivity, specificity, and area under the receiver operating characteristic curve at thresholds of apnea-hypopnea index ≥ 15 events/h were, respectively, sensitivity (Se)15 = 88.0%, specificity (Sp)15 = 88.6%, and area under the receiver operating characteristic curve (AUROC) 15 = 0.926. At the threshold of apnea-hypopnea index ≥ 30 events/h, results included Se30 = 86.0%, Sp30 = 91.2%, AUROC30 = 0.954. The average total sleep time from PSG and the Withings Sleep Analyzers was 366.6 (61.2) and 392.4 (67.2) minutes, sleep efficiency was 82.5% (11.6) and 82.6% (11.6), and wake after sleep onset was 62.7 (48.0) and 45.2 (37.3) minutes, respectively. Conclusions:Withings Sleep Analyzers accurately detect moderate-severe sleep apnea syndrome in patients suspected of sleep apnea syndrome. This simple and automated approach could be of great clinical value given the high prevalence of sleep apnea syndrome in the general population.