A clinical diagnosis of chronic prostatitis was made on 105 adult males who were subsequently admitted and investigated by Stamey localisation techniques, psychological questionnaires, urine flow studies, cysto-urethroscopy and prostatic biopsy or transurethral prostatectomy. From the Stamey localisation studies and cultures of the tissue obtained at transurethral prostatectomy a diagnosis of bacterial prostatitis was made in 50%, of which half were Staphylococcus albus and half were well recognised urinary pathogens. Other significant pathology was found in 25% and, particularly of note, were 2 patients who presented with chronic cystitis (biopsy negative) and subsequently developed carcinoma of the bladder. Also in this group were 5 unsuspected strictures and 5 patients with poor flow rates but normal endoscopy. Investigations in the remaining 25% were all negative except for a significantly higher incidence of neuroticism when compared with the other groups and controls.