Background - Risk factors for obstructive sleep apnea (OSA) and the development of subsequent cardiovascular (CV) complications differ by sex. We hypothesize that the relationship between OSA and high-sensitivity troponin T (hs-TnT), cardiac structure, and CV outcomes differs by sex. Methods and Results - Seven hundred fifty-two men and 893 women free of CV disease participating in both the Atherosclerosis Risk in the Communities and the Sleep Heart Health Studies were included. All participants (mean age, 62.5±5.5 years) underwent polysomnography and measurement of hs-TnT. OSA severity was defined by using established clinical categories. Subjects were followed for 13.6±3.2 years for incident coronary disease, heart failure, and CV and all-cause mortality. Surviving subjects underwent echocardiography after 15.2±0.8 years. OSA was independently associated with hs-TnT among women (P=0.03) but not in men (P=0.94). Similarly, OSA was associated with incident heart failure or death in women (P=0.01) but not men (P=0.10). This association was no longer significant after adjusting for hs-TnT (P=0.09). Among surviving participants without an incident CV event, OSA assessed in midlife was independently associated with higher left ventricle mass index only among women (P=0.001). Conclusions - Sex-specific differences exist in the relationship between OSA and CV disease. OSA, assessed in midlife, is independently associated with higher levels of concomitantly measured hs-TnT among women but not men, in whom other comorbidities associated with OSA may play a more important role. During 13-year follow-up, OSA was associated with incident heart failure or death only among women, and, among those without an incident event, it was independently associated with left ventricular hypertrophy only in women.