Background: Subclinical hypothyroidism (SCH) and metabolic syndrome (MetS) are two common medical conditions. Thyroid dysfunction, prominently SCH has been described more frequently in MetS patients than general population. SCH affect MetS parameters including high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), plasma glucose and blood pressure. The relation between the two conditions looks like a bi-directional relationship. Objectives: The aim of this study was to investigate the association between SCH and MetS in Egyptian young adults and to study the prevalence of MetS and its components in SCH subjects. Patients and methods: The study was conducted at Zagazig University Hospitals. 602 freshman-year students with no history of medical disease were included in the study. General examination, anthropometric, and routine investigations plus thyroid function tests were done for all. Results: Diastolic hypertension (DBP) and impaired fasting glycaemia (IFG) showed significant differences between SCH and EUT. Among the 602 participants, 23.9 % were diagnosed with MetS and 8.9 % with SCH. MetS was found in 22.4 % in the euthyroidism (EUT) group and in 39 % in the SCH group. SCH was found in 14.6 % in subjects with MetS and in 7.2% in non- MetS subjects. There was a significant association between MetS and SCH (χ2=7.3, p˂0.05). Weight, BMI, and DBP were the significant predictors for SCH in patients with MetS. Conclusions: It could be concluded that there is a significant association between MetS and SCH. DBP and IFG show significant difference between SCH and EUT.