OBJECTIVE: We investigated the incidence of the metabolic syndrome and assessed the effect of smoking status and weight change on incident metabolic syndrome. RESEARCH DESIGN AND METHODS: This study included 4,542 men without metabolic syndrome at baseline who were followed for an average of 3 years. Subjects were divided into four categories according to smoking status at baseline and at the 3-year follow-up. RESULTS: The overall incidence of metabolic syndrome was 10.6%: 8.0% in nonsmokers, 7.1% in new smokers, 17.1% in ex-smokers, and 13.9% in sustained smokers (P < 0.001). In a multivariate regression model, ex-smokers had significantly increased odds for incident metabolic syndrome with a mean 1.45 (95% CI 1.06-1.98) compared with sustained smokers. This was no longer significant after including weight change. CONCLUSIONS: Smoking cessation within 3 years may be a higher risk factor for incident metabolic syndrome than sustained smoking, indicating that weight control in ex-smokers is critical to attenuate the additional risk for incident metabolic syndrome.