Abstract: Objective Toevaluate effects of metabolic syndrome (MS) and MS-relatedparameters on prostate volume in men agedfrom40 to50 years. Methods A total of 438 men agedfrom40 to50 years admittedtoour hospital fromJanuary 2010 toDecember 2013 were enrolledin this study. The correlations of prostate volume with MS and MS-relatedparameters were evaluated. Results Prostate volume was not significantly larger in MS group(18.66±6.26) cc than in non-MS group(17.11±3.41) cc, P＜0.05. Comparedwith non-MS group, the prostate volume in subjects with abnormal fasting plasma glucose FPG, (18.99±5.58)cc and abnormal waist circumference WC, (19.22±5.54) cc were significantly larger (P ＜ 0.05). The logistic regression analysis showedthat FPG level and WC hadsignificantly positive correlation with prostate volume (P ＜ 0.05). Conclusion Groups with abnormal FPG and WC have larger prostate volume than normal groups, which are the important factors in prostate volume enlargement in men agedfrom40 to50 years.