ABSTRACT Black women experience disproportionately high rates of hypertension compared to women of other racial and ethnic groups, and their blood pressure (BP) control rates are well below targets despite high levels of awareness and treatment. There is an urgent need for effective nonpharmacological strategies beyond lifestyle behavior change to improve hypertension and cardiovascular disease (CVD) outcomes in this understudied population. Chronic psychosocial stress is associated with hypertension and CVD. Black women are exposed to both race- and gender-based stressors and may employ coping strategies (e.g., emotion suppression, self- care postponement) that increase vulnerability to stress. While many stressful events and circumstances cannot be avoided, adaptive coping can mitigate adverse effects of stress exposure. Mindfulness-based cognitive therapy (MBCT) is an evidence-based program that teaches meditation practices and cognitive strategies to reduce perceived stress and negative emotions. Qualitative research supports the cultural relevance of mindfulness interventions for Black women but clinical trial evidence in this population is limited. Further, the burdensome nature of traditional in-person MBCT poses a significant barrier to participation. We have adapted MBCT for delivery to small groups by telephone (MBCT-T) and our preliminary data support the feasibility, acceptability and effects of the intervention. We propose an RCT to evaluate effects of MBCT-T on BP and psychological outcomes in Black women with uncontrolled hypertension in the Jackson Heart Study (JHS) - a longitudinal cohort study designed to investigate the causes of CVD in Blacks. A sample of 300 female JHS participants with uncontrolled hypertension will be enrolled and randomized to MBCT-T or telephone-based support groups (TSG), an active comparison condition. Both programs involve 8 weekly group-based phone sessions. The primary outcome is home (HBP), a better predictor of CVD risk than clinic BP, measured for 7 days at baseline and 3- and 6-month follow-up with validated wireless devices. Secondary outcomes are perceived stress and depressive symptoms. Measures of chronic stress, coping, resilience and potential psychological, social and behavioral mediators of intervention effects will be assessed. Data from the three prior JHS exams and 20 years of annual follow-up data will also be used to characterize long-term levels of psychosocial factors that may help to explain variability in treatment response. The specific aims are to: (1) Test the hypothesis that MBCT-T will be associated with greater 6-month reductions in systolic BP vs. TSG; (2) Test the hypothesis that MBCT-T will be associated with greater 6-month reductions in perceived stress and depressive symptoms vs. TSG; and (3) Explore potential mediators and moderators of intervention effects on BP and secondary outcomes. Findings will advance understanding of stress, coping and effects of mindfulness ...