Chronic stress and major depressive disorder are associated with accelerated cellular aging, indicated by shortened telomeres in peripheral blood mononuclear cells (PBMCs). Psychological distress is also related to greater oxidative stress, a known cause of telomere shortening. The primary aim of the proposed research is to determine whether mindfulness meditation reduces oxidative stress and increases telomerase activity in PBMCs among highly stressed, overweight women. The secondary aim is to examine possible mediators of these effects by correlating changes in psychological processes (self-report mindfulness, perceived stress, anxiety) and neuroendocrine function (diurnal cortisol rhythms, dexamethasone suppression) with changes in oxidative stress and telomerase activity. This study would be a sub-study of a current randomized waitlist controlled trial of a 3-month Mindfulness-Based Stress Reduction intervention aimed at improving eating patterns, neuroendocrine arousal, and reducing metabolic syndrome risk among overweight women. This research addresses a novel question of whether mindfulness meditation slows cell aging processes and will offer insights into the underlying biological mechanisms by which mindfulness may increase longevity.