This study evaluates the relationship between diabetes mellitus and depression care among non-elderly Medicaid beneficiaries, using claims data from the 1995 State Medicaid Research Files for Alabama, Georgia, New Jersey, and Wisconsin. Presence of comorbid diabetes was found to be significantly associated with a higher rate of depression diagnosis. Among those who were diagnosed as depressed, treatment of comorbid diabetes was associated with a higher rate of antidepressant treatment than among depression-diagnosed patients who did not also have diabetes. However, among patients with diabetes and depression, a quarter received only tricyclic antidepressants. Controlling for other characteristics, African Americans diagnosed with depression were less likely to receive antidepressant treatment and, if they did receive such treatment, more likely to receive the older tricyclic drugs. These findings raise concern for glycemic control among patients with diabetes and depression treated with tricyclic antidepressants in a low-income Medicaid population. Among depressed Medicaid beneficiaries with diabetes, there are racial differences with regard to quality of mental health care in the presence of diabetes.