Major depressive disorder (MDD) is prevalent in clinical weight-loss settings and predicts poor weight-loss outcomes. It is unknown whether the severity of depressive symptoms among those with MDD is associated with diet quality or physical activity levels. This knowledge is important for improving weight-loss treatment for these patients. It was hypothesized that more severe depression is associated with poorer diet quality and lower physical activity levels among individuals with obesity and MDD. Participants were 161 women with current MDD and obesity enrolled in the baseline phase of a weight-loss trial between 2007 and 2010. Depression severity was measured with the Beck Depression Inventory II. The Alternate Healthy Eating Index was applied to data from three 24-hour diet recalls to capture overall diet quality. Daily metabolic equivalents expended per day were calculated from three 24-hour physical activity recalls. Greater depression severity was associated with poorer overall diet quality (estimate=-0.26, standard error 0.11; P=0.02), but not with physical activity (estimate=0.07, standard error 0.05; P=0.18), in linear regression models controlling for income, education, depression-related appetite change, binge eating disorder, and other potential confounds. Associations with diet quality were primarily driven by greater intake of sugar (r=0.20; P<0.01), saturated fat (r=0.21; P<0.01), and sodium (r=0.22; P<0.01). More severe depression was associated with poorer overall diet quality, but not physical activity, among treatment-seeking women with MDD and obesity. Future studies should identify mechanisms linking depression to diet quality and determine whether diet quality improves with depression treatment. All rights reserved.