Aims Urinary bladder dysfunction is a frequent complication of diabetes mellitus in adults. The aim of this study is to determine the early disturbances of the detrusor contractility in children, and adolescents with type 1 diabetes. Materials and Methods The bladder urine flow parameters were investigated in 37 children with type 1 diabetes, 10/37 with cardiovascular autonomic dysfunction (CAD) voided 482 ± 128 mils (Group A), 27/37 without CAD voided 258 ± 52 mils (Group B). From an earlier uroflow screening study 20 healthy children formed group control A, who had voided 488 ± 94 mils, and another 30 healthy children formed group control B, who had voided 260 ± 50 mils. The compared groups were matched for voided volume, age, weight, and height. There was no evidence of urinary tract abnormalities in any of the children. Results Time to maximum flow was longer in both diabetic groups as compared with controls (P