OBJECTIVE To estimate and compare the prevalence and associated bother of lower urinary tract symptoms (LUTS) in the general populations of the USA, UK and Sweden using current International Continence Society (ICS) definitions, as no previous population-based studies evaluating the prevalence of LUTS in the USA, using the 2002 ICS definitions, have been conducted. SUBJECTS AND METHODS This cross-sectional, population-representative survey was conducted via the Internet in the USA, the UK and Sweden. Members of Internet-based panels were randomly selected to receive an e-mailed invitation to participate. If interested, respondents selected a link to an informed consent page, followed by the survey. Participants were asked to rate how often they experienced individual LUTS during the previous 4 weeks, on a five-point Likert scale, and, if experienced, how much the symptom bothered them. Descriptive statistics were used to summarize and present the data. RESULTS Responses rates for the USA, the UK and Sweden were 59.6%, 60.6% and 52.3%, respectively, with a final sample of 30 000 (USA 20 000; UK 7500; Sweden 2500). The mean age (range) of the participants was 56.6 (40-99) years; the mean percentages for race were 82.9% white, 6.7% black, 6.0% Hispanic and 4.4% Asian/other. The prevalence of LUTS was defined by two symptom frequency thresholds, i.e. at least 'sometimes' and at least 'often' for all LUTS except incontinence, where frequency thresholds were at least 'a few times per month' and at least 'a few times per week'. The prevalence of at least one LUTS at least 'sometimes' was 72.3% for men and 76.3% for women, and 47.9% and 52.5% for at least 'often' for men and women, respectively. For most LUTS, at least half of the participants were bothered 'somewhat' or more using a frequency threshold of at least 'sometimes'. For a threshold of at least 'often', 'somewhat' or more bother was reported by ≥70% of participants except for terminal dribble in men and split stream in women. CONCLUSION In this large population study of three countries, LUTS are highly prevalent among men and women aged >40 years. In general, LUTS experienced 'often' or more are bothersome to most people.