Objectives: Elevated serum uric acid (UA) has been known to be associated with the prevalence of metabolic syndrome (MetS). However, no prospective studies have examined whether serum UA levels are actually associated with the development of MetS. We performed a prospective study to evaluate the longitudinal effects of baseline serum UA levels on the development of MetS. Methods: A MetS-free cohort of 14 906 healthy Korean men, who participated in a medical check-up program in 2005, was followed until 2010. MetS was defined according to the Joint Interim Statement of the International Diabetes Federation Task Force on Epidemiology and Prevention. Cox proportional hazards models were performed. Results: During 52 466.1 person-years of follow-up, 2428 incident cases of MetS developed between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95% confidence intervals) for incident MetS for the second, the third, and the fourth quartile to the first quartile of serum UA levels were 1.09 (0.92-1.29), 1.22 (1.04-1.44), and 1.48 (1.26-1.73), respectively (p for trend <0.001). These associations were also significant in the clinically relevant subgroup analyses. Conclusions: Elevated serum UA levels were independently associated with future development of MetS in Korean men during the 5-year follow-up period.