["To determine whether interdependence in couples' sleep (sleep-wake concordance i.e., whether couples are awake or asleep at the same time throughout the night) is associated with two markers of CVD risk, ambulatory blood pressure (BP) and systemic inflammation.", 'Cross-sectional analysis.', 'Community-based study.', 'Forty-six adult couples without known sleep disorders, ages 18-45 years.', "Percent sleep-wake concordance, the independent variable, was calculated for each individual using actigraphy. Ambulatory BP monitors measured BP across 48 hours. Dependent variables included mean sleep systolic BP (SBP) and diastolic BP (DBP), mean wake SBP and DBP, sleep-wake SBP and DBP ratios, and C-reactive protein (CRP). Mixed models were used and were adjusted for age, sex, education, race, and body mass index. Higher sleep-wake concordance was associated with lower sleep SBP (b = -.35, SE = .01) and DBP (b = -.22, SE = .10) and lower wake SBP (b = -.26, SE = .12; all p's < .05). Results were moderated by sex; for women, high concordance was associated with lower BP. Men and women with higher sleep-wake concordance also had lower CRP values (b = -.15, SE = .03, p < .05). Sleep-wake concordance was not associated with wake DBP or sleep/wake BP ratios. Significant findings remained after controlling for individual sleep quality, duration, and wake after sleep onset."] Is sleep-wake concordance in couples inversely associated with cardiovascular disease risk markers?