Background and aims: Although high serum uric acid (SUA) at baseline has been linked to increased risk for metabolic syndrome (MetS), the association of longitudinal SUA changes with MetS risk is unclear. We aimed to examine the effect of distinct SUA trajectories on newonset MetS risk by sex in a Chinese cohort. Methods and results: A total of 2364 women and 2770 men who were free of MetS in 2013 were enrolled in this study and followed up to 2018. Group-based trajectory modeling was applied to identify SUA trajectories. Cox proportional hazards model was used to evaluate the association between SUA trajectory and new-onset MetS. The dose-response relationship between SUA trajectories and MetS risk was examined by treating trajectory groups as a continuous variable. During a median follow-up of 48.0 months, 311 (13.16%) women and 950 (34.30%) men developed MetS. SUA trajectories (2013-2018) were defined as four distinct patterns in both women and men: ?low?, ?moderate?, ?moderate-high?, and ?high?. Compared with ?low ? SUA trajectory, the adjusted hazard ratio for incident MetS among participants with ?moderate?, ?moderatehigh? and ?high? trajectory was in a dose-response manner: 1.75 (95% CI: 1.08-2.82), 1.94 (95% CI: 1.20-3.14), and 3.05 (95% CI: 1.81-5.13), respectively, for women; 1.20 (95% CI: 0.97 -1.49), 1.48 (95% CI: 1.19-1.85), and 1.66 (95% CI: 1.25-2.21), respectively, for men. Conclusions: Elevated SUA trajectories are associated with increased risk for new-onset MetS in women and men. Monitoring SUA trajectories may assist in identifying subpopulations at higher risk for MetS. ? 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.