OBJECTIVE: To evaluate the effectiveness of self management as a first line intervention for men with lower urinary tract symptoms. DESIGN: Randomised controlled trial. SETTING: A teaching hospital and a district general hospital in London. PARTICIPANTS: 140 men (mean age 63 (SD 10.7) years), recruited between January 2003 and April 2004, referred by general practitioners to urological outpatient departments with uncomplicated lower urinary tract symptoms. INTERVENTIONS: Self management and standard care (n=73) or standard care alone (n=67). The self management group took part in three small group sessions comprising education, lifestyle advice, and training in problem solving and goal setting skills. MAIN OUTCOME MEASURES: The primary outcome measure was treatment failure measured at 3, 6, and 12 months. Symptom severity (international prostate symptom score; higher scores represent a poorer outcome) was used as a secondary outcome. RESULTS: At three months, treatment failure had occurred in 7 (10%) of the self management group and in 27 (42%) of the standard care group (difference=32%, 95% confidence interval 18% to 46%). Corresponding differences in the frequency of treatment failure were 42% (27% to 57%) at six months and 48% (32% to 64%) at 12 months. At three months, the mean international prostate symptom score was 10.7 in the self management group and 16.4 in the standard care group (difference=5.7, 3.7 to 7.7). Corresponding differences in score were 6.5 (4.3 to 8.7) at six months and 5.1 (2.7 to 7.6) at 12 months. CONCLUSIONS: Self management significantly reduced the frequency of treatment failure and reduced urinary symptoms. Because of the large observed benefit of self management, the results of this study support the case for a large multicentre trial to confirm whether self management could be considered as first line treatment for men with lower urinary tract symptoms. TRIAL REGISTRATION: National Research Register N0263115137; Clinical trials NCT00270309 [ClinicalTrials.gov].