Patients with diabetes and comorbid depression have an increased risk of complications. In a repeated panel cross-sectional study, we investigated the effect of depression care on glycemic control for adults with diabetes. Local health plan provided secondary data (N=29,227) that contained depression information and overall health risk calculated by Johns Hopkins ACG software using diagnosis code, visits, and medication claims. This data was matched with A1c, demographics, and neighborhood characteristics. Study outcome is A1c change. Predictor of interest is depression treatment: (1) no depression in either year, (2) new onset is not treated in prior year but treated in sequential year, (3) past is treated in one year and none in sequential year, and (4) persistent is received treatment in both years. Covariates are age, sex, health risk, insurance types, and neighborhood characteristics. The analysis is a multiple linear regression model using a difference-in-differences framework. Adjusting for covariates, new onset of depression treatment was associated with better diabetes control, A1c decreased by 0.072 (p=0.025), compared to no depression. Compared to no depression, past depression treatment was associated with lower diabetes control, A1c increased by 0.071 (p=0.007). Persistent depression treatment had A1c change not different from no depression group (p=0.731). Among patients with diabetes, past depression treatment appeared to have poorer glycemic control compared with those not depressed. New onset of depression treatment appeared to improve glycemic control. New diagnosis of depression increased patient contact with provider. A decline in diabetes control among patients received depression treatment in the past, may be related to a change in contact with provider. Future studies could investigate whether patient visit with providers was affected by a change in depression and examine if A1c testing rate correlates with health service utilization. Disclosure H.N. Fu: None. A.M. Raiter: None. C. Carlin: None. K.A. Peterson: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R18DK110732)