Metabolic Syndrome consists in a group of metabolic changes, being the most important problem insulin resistence. Other important components of this syndrome are abdominal obesity, hypertension and hyperlipidemia /hypercholestrolemia. It was demonstrated that psychiatric patients have a greater risk to develop metabolic syndrome with a prevalence of 41%. Prevalence of this syndrome in psychiatric male patients is 138% higher than in general population and in female patients 251% higher. Some of the factors that can explain this increase of metabolic risk in psychiatric patients are psychiatric drugs. We preformed a systematic review of literature published until June, 2007, by means of MEDLINE. Studies reviewed include clinical cases, reviews, analytic and observational studies. We selected 72 articles. Authors pretend to understand the mechanisms, by which, different psychiatric drugs can influence metabolic syndrome, and strategies for prevention of this situation.