In patients with type 2 diabetes (T2DM), depression increases the risk of poor glycemic control and decreases adherence to medications, exercise, and diet. Studies have shown an inverse relationship between plasma vitamin D (VD) level and depression risk. However, there are few interventional trials of African Americans (AAs), a demographic with higher prevalence of diabetes, depression, and VD deficiency. This randomized controlled trial evaluated the efficacy of vitamin D