A total of 48 patients with BPH were studied before and after TURP. Initial diagnostic evaluation consisted of clinical examination, IPSS, uroflowmetry, cystometry, and "pressure-flow" study. Contribution of the important urodynamic measurements for the favourable symptomatic outcome was evaluated. There was significantly better result in patients with severe symptoms preoperatively (p = 0.03), low preoperative Qmax (p = 0.03), and presence of obstruction (p = 0.004), especially in patients with normal or strong detrusor contraction. Preoperative volume of residual urine as well as detrusor instability were not important for the symptomatic outcome. IPSS and uroflowmetry should not be treated as optional diagnostic tests. They improved the percentage of patients with an excellent symptomatic outcome from 62.5% to 90% (p = 0.04). "Pressure-flow" study is the reliable method for the achievement of excellent symptomatic outcome, but not significantly better than uroflowmetry and IPSS together. "Pressure-flow" study should be performed only in inconclusive preoperative cases.