Background: Metabolic Syndrome (MS) is identified as a cluster of risk factors that significantly increase the risk of diabetes, cardiovascular disease, and stroke. It is characterized by obesity, hyperglycemia, dyslipidemia, and hypertension. Multiple definitions and criteria of MS exist. The most widely used set of criteria are the US National Cholesterol Education Program (NCEP) ATP III and the International Diabetes Federation (IDF), both of which are used in this study. Due to different defining criteria and population demographics, the prevalence of MS varies widely across countries, regions, and continents.Objective: This study investigates the prevalence and risk factors of metabolic syndrome among primary healthcare attendees in Riyadh, Saudi Arabia.Methods: A cross-sectional study was conducted over 12 months at the Prince Sultan Military Medical City (PSMMC) Wazzarat Center in Riyadh, Saudi Arabia, involving 262 participants. The study aimed to determine the prevalence and predictors of MS among primary healthcare attendees using ATP III and IDF criteria. Participants were assessed for sociodemographic features, comorbidities, vital signs, and laboratory data related to MS. Statistical analysis utilized R v 4.3 for descriptive statistics, Pearson correlation, Chi-square tests for categorical variables, and the Mann-Whitney test for continuous variables.Results: Among the study participants, 20.2% met the criteria for MS according to ATP III, and 19.9% according to IDF criteria, with a strong concordance between the two (Kappa statistic = 0.92, P < 0.001). The median age of individuals with MS was significantly higher (45 years) than those without (35 years, P < 0.001). Significant predictors included age, with BMI and fasting blood glucose showing a strong positive correlation (r > 0.5, P < 0.001). Notably, 60.7% of the cohort were medically free from conditions contributing to MS.Conclusion: The prevalence of MS among primary healthcare attendees in Riyadh, as defined by ATP III and IDF criteria, underscores the importance of age and lifestyle factors as predictors. The findings advocate for targeted preventive strategies focusing on lifestyle modifications to mitigate the risk of MS. Further research is suggested to explore the long-term impact of these interventions.