Serum thyroid hormone and TSH levels were determined in the worker of automobile workshops and petrol filling stations workers through ELISA. A total of 44 exposed individuals (25 automobile workshop and 19 petrol filling station workers) having an age range of 24-45 were recruited from Lahore city. Twenty one (21) healthy controls of the same age range were recruited from University of the Punjab, Lahore. A significant decline (P ≤ 0.05) of T3 was seen in automobile workers as compared with controls. Both, automobiles workshop workers and petrol station workers demonstrated a significant decline of T4 as compared to controls. Mild elevation of TSH was present in both Automobiles and Petrol filling Station workers as compared to controls. Reduced levels of T3 and T4 and elevated TSH may lead to hypothyroidism in the workers exposed to these environments.