The aim of this study was to evaluate the association between dietary phytochemical index (PI) and occurrence of metabolic syndrome and its components during a 3 year follow up of Tehranian adults. Materials and Methods: This longitudinal study was conducted within the framework of Tehran Lipid and Glucose Study, between the third (2006-2008) and fourth phases (2009-2011). Dietary intakes were collected using a validated semi-quantitative food frequency questionnaire at baseline. The predictor role of dietary phytochemicals for risk of abdominal obesity, fasting glucose intolerance, hypertriglyceridemia, hypertension and metabolic syndrome-according to the international criteria-were evaluated using regression logistic models after adjustment of confounding factors. Results: The mean of dietary phytochemical index was 29.8±12.3 at baseline. Higher intake of phytochemical-rich foods was associated with a significant descending trend in risk of metabolic syndrome, abdominal obesity, hypertriglyceridemia and hypertension (P for trend < 0.05). Subjects in the highest quartile of dietary phytochemicals intake had a thirty-nine percent lower risk of abdominal obesity (0.61 95%CI: 0.36-0.99), thirty seven percent lower risk of hypertriglyceridemia (0.63 95%CI: 0.38-0.99) and a forty four percent lower risk of hypertension (0.56 95%CI: 0.35-0.90), compared with those in the lowest quartile. Conclusion:  Our findings indicate that higher intakes of phytochemical-rich foods can decrease the risk of metabolic syndrome and related risk factors.