OBJECTIVE -Depression is associated with poor glycemic control and complications in people with type 1 diabetes. We assessed the prevalence of depression and antidepressant medication use among adults with and without type 1 diabetes and the association between depression and diabetes complications. -In 2006, the Coronary Artery Calcification in Type 1 Diabetes Study applied the Beck Depression Inventory II (BDI-II) to 458 participants with type 1 diabetes (47% male, aged 44 Ϯ 9 years, type 1 diabetes duration 29 Ϯ 9 years) and 546 participants without diabetes (nondiabetic group) (51% male, aged 47 Ϯ 9 years). Use of antidepressant medication was self-reported. Depression was defined as a BDI-II score Ͼ14 and/or use of antidepressant medication. Occurrence of diabetes complications (retinopathy, blindness, neuropathy, diabetes-related amputation, and kidney or pancreas transplantation) was self-reported. RESEARCH DESIGN AND METHODSRESULTS -Mean BDI-II score, adjusted for age and sex, was significantly higher in participants with type 1 diabetes than in nondiabetic participants (least-squares mean Ϯ SE: 7.4 Ϯ 0.3 vs. 5.0 Ϯ 0.3; P Ͻ 0.0001). Type 1 diabetic participants reported using more antidepressant medications (20.7 vs. 12.1%, P ϭ 0.0003). More type 1 diabetic than nondiabetic participants were classified as depressed by BDI-II cut score (17.5 vs. 5.7%, P Ͻ 0.0001) or by either BDI-II cut score or antidepressant use (32.1 vs. 16.0%, P Ͻ 0.0001). Participants reporting diabetes complications (n ϭ 209) had higher mean BDI-II scores than those without complications (10.7 Ϯ 9.3 vs. 6.4 Ϯ 6.3, P Ͻ 0.0001).CONCLUSIONS -Compared with nondiabetic participants, adults with type 1 diabetes report more symptoms of depression and more antidepressant medication usage. Depression is highly prevalent in type 1 diabetes and requires further study on assessment and treatment. Diabetes Care 32:575-579, 2009