This review considers the use of the first selective blocker of the cannabinoid receptor type 1, rimonabant, to reduce weight and improve cardiovascular disease risk factors in obese patients with metabolic syndrome or multiple cardiovascular disease risk factors. In 4 large trials-Rimonabant in Obesity (RIO)-Lipids, RIO-Europe, RIO-North America, and RIO-Diabetes-after 1 to 2 years of treatment, rimonabant (20 mg/day) led to a significantly greater weight loss and reduction in waist circumference compared with placebo. Treatment with rimonabant was also associated with other favorable changes, including better glycemic control in type 2 diabetes mellitus, improved lipid profile, reduced blood pressure, increased adiponectin levels, fall in high-sensitivity C-reactive protein concentrations, and an overall decrease in the prevalence of the metabolic syndrome. Initial experience with rimonabant shows that it is generally well tolerated with the most common side effect of mild nausea. Rimonabant may be a useful adjunct to lifestyle and behavior modification in the treatment of obese subjects with metabolic syndrome or multiple cardiometabolic risk factors.