Background: Although previous studies have highlighted the importance of serum uric acid as a risk factor of metabolic syndrome, no study has previously used a national Korean survey to examine the association between serum uric acid level and metabolic syndrome. This study aimed to investigate this association among Korean adults, to determine whether it varies by age and gender, and to identify optimal serum uric acid level cutoffs for predicting the presence of metabolic syndrome by gender and age. Methods: We included 5,758 Korean adults (aged ≥ 19 years) who participated in the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-1), 2016. Logistic regression analyses were performed to examine the association between serum uric acid and the presence of metabolic syndrome. Receiver operating characteristic analyses were used to assess optimal uric acid cutoff values for predicting the presence of metabolic syndrome. Results: High serum uric acid levels were found to be associated with risk of metabolic syndrome. Area under the receiver operating characteristic curve (AUC) analyses of uric acid levels for the detection of metabolic syndrome produced good performances. Women subjects had significantly higher AUC values than men subjects, but this gender difference may also have been influenced by age. Among men, AUC values of those in their 20s, 30s, or 40s were significantly higher than those in their 70s (P < 0.05). The optimal uric acid cutoff was 6.05 mg/dL for men and 4.45 mg/dL for women, and men had higher cutoffs than women in all age groups. Conclusion: Among Korean adults, serum uric acid levels were found to be strongly associated with the presence of metabolic syndrome. More importantly, our findings suggest that derived optimal cutoff values of uric acid might offer a useful means of diagnosing metabolic syndrome in clinical settings.