OBJECTIVES: Metabolic syndrome is a highly prevalent health problem within the adult population in developing countries. We aimed to study the association of physical activity levels and metabolic risk factors among Malay adults in Malaysia. DESIGN: Cross-sectional. METHODS: Body mass index, waist circumference, and systolic/diastolic blood pressure, fasting blood glucose, fasting triglyceride and high-density lipoprotein cholesterol levels were measured in 686 Malay participants (aged 35-74 years). Self-reported physical activity was obtained with the validated International Physical Activity Questionnaire (Malay version) and categorized into low, moderate or high activity levels. RESULTS: Individuals who were classified as overweight and obese predominated (65.6%). On the basis of the modified NCEP ATP III criteria, metabolic syndrome was diagnosed in 31.9% of all participants, of whom 46.1% were men and 53.9% were women. The prevalence of metabolic syndrome among participants with low, moderate or high activity levels was 13.3%, 11.7% and 7.0%, respectively (p<0.001). Statistically significant negative associations were found between a number of metabolic risk factors and activity categories (p<0.05). The odds ratios for metabolic syndrome in the moderate and high activity categories were 0.42 (95% CI: 0.27-0.65) and 0.52 (95% CI: 0.35-0.76), respectively, adjusted for gender. CONCLUSIONS: Moderate and high activity levels were each associated with reduced odds for metabolic syndrome independent of gender. Although a slightly lower prevalence of metabolic syndrome was associated with high activity than with moderate activity, potential health benefits were observed when moderate activity was performed.