The metabolic syndrome (MetS) is a cluster of risk factors that predispose individuals to cardiovascular disease. Therapeutic lifestyle changes, including increased physical activity, are recommended for the prevention and treatment of MetS. The purpose of this study was to examine the relationship between physical activity and MetS in Canada. The sample included 6406 men and 6475 women aged 18-64 y who were participants in the Canadian Heart Health Surveys (1986-1992). MetS was classified using criteria modified from the US National Cholesterol Education Program. Participants were deemed physically active if they were active at least once each week for at least 30 min, engaging in strenuous activity some of the time. The relationship between physical activity and MetS was assessed using logistic regression, with age, smoking, alcohol consumption, and income adequacy as covariates. A total of 14.4% of Canadians had MetS and 33.6% were physically active. The odds ratio for MetS was 0.73 (95% confidence interval (CI): 0.54-0.98; p < 0.05) for physically active vs. physically inactive participants. The corresponding odds ratios were 0.45 (95% CI: 0.29-0.69; p < 0.001) and 0.67 (95% CI: 0.44-1.02; p = 0.06) for men and women, respectively. In summary, physical activity was associated with lower odds of MetS, particularly in men. Further research is required to determine the effectiveness of physical activity in the treatment of MetS.