The urodynamic findings in 33 patients with cerebral palsy referred with lower urinary tract symptoms were reviewed. Difficulty urinating was the predominant symptom in approximately half of the patients and half of these also had hyperreflexia and urgency when full. Three patients had varying degrees of retention and the remaining 14 had difficulty initiating a urinary stream. The other half had urgency incontinence as a major presenting symptom and this was associated in nearly all cases with hyperreflexia. There were 10 adults: 5 with difficulty urinating and 5 with urgency. The more serious manifestations, such as retention, were found only in the adults, suggesting that difficulty urinating may progress in adult life. Classical detrusor-sphincter dyssynergia with bladder wall changes was seen only once, and the cause of difficulty urinating in the other patients seemed to be due to a lack of voluntary control over and the hypertonus of the pelvic floor.