Uroflowmetry has been performed on 140 occasions in 90 patients with hypospadias before and after reconstructive surgery. Children with hypospadias tend to have a lower maximum urinary flow rate for volume voided than the general population, lying around the population 5th centile. This is observed before any surgery is performed, and appears from our cross-sectional data to be unaffected by surgery. Uroflowmetry has proved a useful and economical means of gaining an objective assessment of urinary function in this group of patients. Further longitudinal studies to confirm this cross-sectional study would be useful.