Pressure-flow studies consist of simultaneously measuring urine flow rate and the detrusor pressure required to achieve this flow rate. It is the reference test for the diagnosis of bladder neck obstruction, characterized by the combination of high detrusor pressure and low urine flow rate. Pressure-flow studies are essentially indicated in the presence of voiding disorders of undetermined aetiology, with a discordance between clinical history, clinical examination and uroflowmetry, or in the presence of neurological disease associated with benign prostatic hyperplasia (BPH), or when surgical treatment of BPH is associated with particular morbidity in order to document bladder neck obstruction.