The metabolic syndrome is a health condition characterized by abdominal obesity, dyslipidemia, elevated blood pressure and impaired glucose tolerance, with increasing prevalence. Adherence to the Mediterranean diet seems to exert beneficial effects regarding the metabolic syndrome prevalence and progression. Thus, we performed an updated systematic review of studies which have evaluated the effect of the Mediterranean dietary pattern on the metabolic syndrome. This was a systematic review of epidemiological observational studies and clinical trials. English language publications in the databases PubMed, Embase, Scopus, until May 31, 2013, were included in this review. New evidence from prospective cohort studies, cross-sectional studies and clinical trials supports the beneficial role of adherence to the Mediterranean dietary pattern regarding metabolic syndrome presence and progression. Considering the magnitude of metabolic syndrome, efforts should be made to encourage adoption of this pattern in Mediterranean countries and similar dietary pattern in countries where metabolic syndrome is prevalent.