BACKGROUND: Metabolic syndrome (MS) is associated with subsequent development of type 2 diabetes and cardiovascular disease in the general population. The impact of MS on mortality in patients with stable coronary heart disease is less well defined, and the association of prognosis to gender is unknown. METHODS: 1041 patients with stable coronary heart disease, referred for elective coronary angiography were included in this study. At baseline, history of hypertension, body mass index, lipids, fasting plasma glucose, and insulin were recorded. All-cause mortality was determined after a median follow-up of 9.2 years. RESULTS: At follow-up 296 (28%) patients had died. 315 (30%) patients had MS based on the definition by the World Health Organization. Patients with MS more frequently had diabetes and three-vessel disease of the coronary arteries. Men had a more severe risk profile than women. In a multivariable Cox regression analysis, MS was not associated with excess mortality risk in the overall population [adjusted HR=1.3 (95% CI: 0.7-2.3), p=0.43]. In gender specific analyses MS increased risk of all-cause mortality in women [adjusted HR=2.2 (95% CI: 1.1-4.3), p=0.02], but not in men [adjusted HR=1.0 (95% CI: 0.5-1.9), p=0.93]. CONCLUSIONS: MS provides prognostic information in women, but not in men. This association was independent of conventional cardiovascular risk factors including previously unrecognised diabetes, and angiographic coronary artery disease.