To determine the prevalence of troublesome lower urinary tract symptoms (LUTS) in men and women in the community. Interview-based prevalence survey. Metropolitan and rural communities in South Australia, September, 1995. Probability sample of 1204 men and 1686 women (aged over 18 years) weighted to reflect the age and sex distribution of the South Australian population. Presence of storage (irritative) and voiding (obstructive) symptoms, based on the International Prostate Symptom Score questionnaire; satisfaction with urinary condition (quality-of-life measure); and visits to a doctor for urinary symptoms in the preceding 12 months. The prevalence of one or more troublesome LUTS was 26% (318/1204) for men and 39% (662/1686) for women (all ages) and 48% (314/649) for men and women over 65. The most common troublesome symptoms in men and women were nocturia and frequency. Symptoms were significantly age-related in men, but less so in women, in whom symptom prevalence exceeded 30% for all age groups. Ten per cent of men (123/1204) and 15% of women (249/1686) had visited a doctor for a urinary problem in the previous 12 months. Nine per cent of men (104/1204) and 16% of women (274/1686) were substantially dissatisfied with their urinary condition. Symptom prevalence and dissatisfaction with urinary condition were significantly associated with visiting the doctor (P < 0.0001), but only 28% (88/318) of men and 27% (179/662) of women with troublesome LUTS saw a doctor, and 63% (65/104) of men and 59% (162/274) of women dissatisfied with their urinary condition did not seek medical help. Although the prevalence of troublesome LUTS in the community is high, the number of people whose quality of life is substantially affected is much lower. The impact of these symptoms upon quality of life is a major reason for patients to see a doctor, yet many who are "bothered" by the symptoms do not do so.