The occurrence of bladder disorders, such as increase in vesical volume, incomplete vesical evacuation, and increase in first morning micturition, as well as its association with certain clinical factors, such as duration of diabetes, age at onset, degree of metabolic control, and symptoms of vesical autonomic neuropathy, were studied in a group of 55 diabetic children using vesical echography. Morning diuresis and vesical volume for age were previously determined in a group of 40 non-diabetic children used as controls. The echographic measurements permitted the estimation of maximum normal vesical volume for each age group, yielding the following distribution: 6-8 years, up to 263.7 ml; 9-11 years, up to 375.7 ml; 12-14 years, up to 445.3 ml. Analyzing first morning micturition by age in the control group, we found the following maximum values: 6-8 years, up to 263.5 ml; 9-11 years, up to 380.1 ml; 12-14 years, up to 394.6 ml; 67.27% of all diabetic children had bladder disorders. It was demonstrated that routine determination of the first morning micturition in the diabetic child would be an excellent index for detecting early disorders of vesical function. The existence of a statistically significant association (p less than 0.05) of poor metabolic control to development of these disorders, as well as to symptoms referred at this level, was confirmed. No other statistically significant association was found between the occurrence of these bladder disorders and other factors such as duration and age at onset of the disease.