Background: Type 1 diabetes is an organ specifc autoimmune disease whose incidence is increasing worldwide. A functional imbalance in cytokine production resulting in dominance of T helper (Th1) over Th2-type response has been suggested to play a critical role in the pathogenesis of type 1 diabetes. Aim: To measure serum concentrations of interleukin (IL)-1ß, IL-2 and IL-4 in children with recently diagnosed type 1 diabetes and to evaluate the autoimmune response measuring glutamic acid decarboxylase (GAD65) and tyrosine phosphatase like (IA-2) autoantibodies. Patients and Methods: 120 diabetic children and 118 age and gender matched control children, were recruited for this study. Circulating levels of IL-1ß, IL-2 and IL-4 were measured by ELISA. GAD65 and IA-2 were measured by RIA. Results: Circulating levels of IL-1ß were elevated in type 1 diabetic children as compared to the control group (9.3±7.3 and 4.9±3.8 pg/ml respectively, p=0,01). Serum concentration of IL-2 was also higher in diabetic patients (19.8±13.1 and 11.3±9.1 pg/ml respectively, p=0,01). No differences in serum IL-4 were observed between diabetics and control. Diabetic children with one or two positive autoantibodies (IA-2 and/or GAD65) had significantly higher levels of IL-1ß and IL-2 and lower levels of IL-4 than diabetic children without positive autoantibodies. High concentrations of IL-1ß were associated with an early onset of the disease. Conclusions: High levels of IL-1ß and IL-2 were found in diabetic children with recent diagnosis of the disease. Diabetics with positive antibodies against GAD65 and IA-2 had higher levels of IL-1ß and IL-2 and lower levels of IL-4 than their counterparts without positive antibodies (Rev Méd Chile 2004; 132: 413-20)