The relationship of diabetes symptoms to current mood and general metabolic control was studied. Symptoms commonly associated with poorly controlled diabetes (e.g., thirst, polyuria, weight loss) were measured in 114 patients with diabetes mellitus (type 1 = 57, type 2 = 57). Scores for these individual symptoms were correlated with glycosylated hemoglobin (HbA1) and depression as measured by the Beck Depression Inventory (BDI). HbA1 was poorly correlated (r less than 0.2) with nine of the eleven symptoms and made a significant independent contribution only to the reporting of polyuria (p = 0.04). In contrast, depression was moderately correlated with nine symptoms and had a significant effect on the reporting of two of three hyperglycemic symptoms, five of six hypoglycemic symptoms, and both nonspecific symptoms of poor control (p less than 0.05 for each). We conclude that many reported symptoms often attributed to diabetes are more related to depressive mood than to a conventional clinical measure of blood glucose control. Diabetes symptoms may be unreliable indicators of poor metabolic control when features suggestive of depression are present.