['To determine whether initial effects on metabolic control and quality of life associated with a behavioral intervention combined with intensive diabetes management (IDM) can be sustained over 1 year in youth implementing intensive therapy regimens.', "Seventy-seven patients (43 females, 95% white) 12 to 20 years (mean = 14.2 +/- 1.9; duration, 8.7 +/- 3.9) electing to initiate IDM were randomly assigned to one of two groups: with or without coping skills training (CST), which consists of 6 small group sessions and monthly follow-up to help youth cope with their lives in the context of diabetes management; skills included social problem solving, cognitive behavior modification, and conflict resolution. Data were collected before the intervention and at 3, 6, and 12 months after the intervention by using the Self-Efficacy for Diabetes Scale, Children's Depression Inventory, Issues in Coping with IDDM, and the Diabetes Quality of Life: Youth scales. Clinical data (glycosylated hemoglobin level, height, weight, adverse effects) were collected monthly.", 'The CST and IDM groups were comparable at baseline. CST subjects had lower glycosylated hemoglobin (P =.001) and better diabetes (P =.002) and medical (P =. 04) self-efficacy, and less impact of diabetes on their quality of life (P =.005) than youth receiving IDM alone after 1 year. In males, CST did not affect adverse outcomes of IDM hypoglycemia, diabetic ketoacidosis, and weight gain, but CST decreased the incidence of weight gain (P =.05) and hypoglycemia in females (P =.03).'] Does coping skills training for youth with diabetes mellitus have long-lasting effects on metabolic control and quality of life?