The objective of the present study is to explore the association between lower urinary tract symptoms (LUTS) and dietary isoflavone in elderly men. In a large prospective cohort of 2000 Chinese men, the association between dietary isoflavone and LUTS were studied using standardized structured questionnaires. Dietary intake was assessed by a modified version of the Block FFQ. LUTS were assessed by the Chinese version of the International Prostatic Symptoms Score. Demographic, lifestyle and other medical information were also collected and were adjusted for in the analysis. After excluding 299 men with history of bladder surgery, bladder or prostate cancer or who were current users of medication for urinary problems, the association between LUTS and dietary isoflavone was explored. A total of 96·2 % of subjects reported some consumption of genistein, glycitein or daidzein. In ordinal multinominal logistic regression, subjects with dietary total isoflavone of more than 5·1 mg were significantly less likely to suffer from more severe LUTS (dietary intake from 5·1 to 9·5 mg: OR 0·59; 95 % CI 0·44, 0·80; from 9·6 to 14·3 mg: OR 0·81; 95 % CI 0·61, 1·09; from 14·4 to 21·7 mg: OR 0·68; 95 % CI 0·51, 0·92; 21·8 mg and above: OR 0·73; 95 % CI 0·54, 0·98) after adjustment for covariates. In this cross-sectional study, we showed a strong inverse association between dietary intake of isoflavone and the risk of LUTS.