BACKGROUND The metabolic syndrome is also known as syndrome X, the insulin resistance syndrome and the deadly quartet. The constellation of metabolic abnormalities includes insulin resistance, glucose intolerance, central obesity, dyslipidaemia and hypertension, as well documented risk factors for cardiovascular disease. When grouped together, they are associated with increased risk of cardiovascular disease. The concept of metabolic syndrome exists at least 80 years. That was first described in the 1920s by Kelin, a Swedish physician as the clustering of hypertension, hyperglycaemia and gout. An overt hypothyroidism is associated with all the parameters of metabolic syndrome, except increase in fasting blood glucose. The objectives of this study is to study the prevalence of thyroid dysfunction in the newly detected Metabolic Syndrome patients and to find out the correlation between the thyroid dysfunction and metabolic syndrome parameters. MATERIALS AND METHODS This is a cross-sectional study and it was conducted at Institute of Diabetology, Madras Medical College and Government General Hospital for a period of 8 months. RESULTS Total number of participants in this study was 60 in number. In this study group, 33 (60%) were females and 27 (40%) were males. On analysis of 60 people for the thyroid dysfunction, 8 were positive which represents 16.7% in percentage. Prevalence of hypothyroidism is 15.0% (overt hypothyroidism 3.3% and subclinical hypothyroidism 11.7%) in metabolic syndrome patients. Only one study subject among the metabolic syndrome found to have subclinical hyperthyroidism (1.7%). There were no overt hyperthyroidism patients in our study. Correlation coefficient values between FT4, TSH and metabolic parameters are not significant in our study. CONCLUSION One sixth of metabolic syndrome patients or every sixth metabolic syndrome had hypothyroidism either overt or subclinical. Exclude the presence of Thyroid dysfunction, while managing metabolic syndrome patients.