This study evaluated gender differences in glycemic control among adolescents with insulin-dependent diabetes mellitus (IDDM). Drawing upon a conceptual model, the role of diabetes-specific and psychological variables in predicting gender differences in adolescents' glycemic control was examined. Following routine appointments for medical care, 42 adolescents with IDDM completed several measures: Test of Diabetes Knowledge and Problem Solving-Revised; Self-Care Inventory; Beck Depression Inventory; and the State-Trait Anxiety Inventory. Metabolic control was assessed via HbA[sub 1c] assays. Findings revealed that girls were in worse metabolic control than boys and reported more symptoms of depression and anxiety. Furthermore, gender differences in metabolic control could be explained by the greater depressive symptomatology reported by adolescent girls. Possible reasons for the linkage between depression and poor metabolic control are discussed, as well as directions for future research and clinical implications.