Patients with neurogenic bladder dysfunction may have an elevated detrusor pressure during the filling or emptying phase, which may result in upper urinary tract dysfunction. Cystometric examination is important in order to evaluate the risk of such complications and the effect of therapeutic intervention. If compliance is low, the cystometric filling rate has to be slow in order to obtain a physiologically representative pressure. In the case of detrusor hyperreflexia, intraindividual variation makes it necessary to perform repeated filling of the bladder in order to get representative values for the amplitude and duration of the detrusor contraction. The clinical significance of these methodological problems is discussed.