Twenty-five diabetics with insulin-dependent condition were examined at the debut of the disease before insulin therapy, as were 10 healthy donors. Under study were relative and absolute counts of T lymphocytes, NK cells, B lymphocytes, DR-T lymphocytes, Th, Ts, and Th/Ts index. Patients' and donors' sera were tested for autoantibodies to P64-69kD antigenic complex. Characteristic features of cellular immunity of patients with newly-detected diabetes were disclosed. Counts of B lymphocytes and Dr-T lymphocytes were increased in all patients. A relationship was revealed between immunoregulatory Th/Ts index and clinical features of insulin-dependent diabetes. Autoantibodies to p64-68 kD andigenic complex were detected in 63-88% of patients with newly detected insulin-dependent diabetes.