Background: Sub-clinical hypothyroidism (SCH), overt hypothyroidism and metabolic syndrome (MetS) are recognized risk factors for atherosclerotic cardiovascular disease and Type 2 diabetes mellitus (DM- II).Thyroid function affects MetS parameters including blood pressure (BP), fasting blood sugar (FBS), serum triglycerides (TG) and high density lipoprotein cholesterol (HDL-C). But the relationship between MetS and thyroid functions is yet to be identified clearly. The present study is to investigate the frequency of MetS in patients of SCH and overt hypothyroidism. Materials and Methods: A hospital based cross–sectional study was conducted at Swastik referral laboratory and research centre. In this study, 50 patients with overt hypothyroidism, 50 patients with SCH and 129 euthyroid controls were enrolled. National Cholesterol Education Program- Adult Treatment Panel III (NCEP-ATP III; 2005) revision criteria were used to diagnose metabolic syndrome. Thyroid function test (TFT: FT3, FT4 and TSH) was done by using chemiluminescence immunoassay (CLIA) and other tests by using a semi-auto analyzer. ANalysis Of VAriance (ANOVA) test was performed using SPSS (version 16.0). Result: There was a significant difference in the mean of the waist circumference (p=0.031), BP systolic (p=0.010), BP diastolic (p<0.001)), FBS (p=0.001), serum HDL-C (p=0.031) and serum TG (p=0.003) between control, subclinical and overt hypothyroidism group (p<0.001). Prevalence of MetS was 25.6 % in euthyroid controls whereas 44.0% in the SCH group and 62.0% in the overt hypothyroid group (p<0.001). Conclusion: Thyroid dysfunction may be responsible for the development of metabolic syndrome.