BACKGROUND Inter-cultural difference in the prevalence of lower urinary tract symptoms (LUTS) has been recognized. The purpose of present study was to evaluate the prevalence of LUTS and the correlation between symptoms with age and urinary flow rate in a community-based sample of Taiwanese men. METHODS Invitation letters were sent out to 4,488 men > or = 40 years old living in Ling-Ya District, Kaohsiung City. All responders were scheduled for thorough history taking, International Prostate Symptom Score (IPSS) assessment, digital rectal examination, serum prostatic specific antigen (PSA) and uroflow determinations. The correlation of IPSS with age, PSA levels and urinary flow rate were evaluated. RESULTS A total of 306 men (6.8%) accepted our invitation; 207 of them had validated data for analysis. The confidence interval was 6.79 at 95% confidence level. Twenty-one men (10.1%) had serum PSA > 4 ng/ml. The median PSA increased with advancing age (p = 0.001). Severe symptoms were reported by 9.7%, while 40.1% reported moderate symptoms. The percentage of men with IPSS > or = 8 increased withage (p < 0.001). There was a positive correlation between IPSS and age (r = 0.380). Negative correlation between IPSS and voided volume (r = -0.255), maximal flow rate (r = -0.363), and mean flow rate (r = -0.401) were also noted. CONCLUSIONS In this community-based study, moderate to severe lower urinary tract symptoms were reported by 50% of assessable men over the age of 40 years. This prevalence was similar to that of Japanese but higher than those of American, French, and Scottish men. The IPSS was positively correlated with age, and negatively correlated with uroflow rate and voided volume. However, because of extremely low and uneven response rates among each age category, this data must be interpreted with caution.