Depression has been linked to greater mortality and morbidity in diabetic patients, but this issue has not been adequately studied in the Islamic Republic of Iran. This cross-sectional study described the prevalence of depression in patients attending a diabetes clinic in Urmia and determined the associated sociodemographic, behavioural and clinical factors. Of 295 patients, 128 (43.4%) had depression scores (≥ 15) on the Beck Depression Inventory. The mean score for all patients was 15.4 (SD 9. 5). Those with depression were significantly older and less educated than those without depression, had a longer duration of diabetes and were more likely to suffer complications. On logistic regression analysis, older age was the only variable significantly associated with depression.