<p> Background: Thyroid hormones play an important role in human metabolism. Hypothyroidism is diagnosed by elevated thyroid stimulating hormone (TSH) and decreased serum levels of T4 or T3 , and is associated with a wide range of metabolic abnormalities. Aims and objectives: To estimate serum lipid profile, serum creatinine, uric acid, haemoglobin levels in newly diagnosed hypothyroid patients and to evaluate the efficacy of the L-thyroxine treatment on the same in Shivamogga population. Materials and methods: We measured serum lipid profile [Total cholesterol (TC), Triglyceride (TG), HDL-Cholesterol (HDL-C), LDL-Cholesterol (LDL-C), VLDL-Cholesterol (VLDL-C)] serum creatinine, uric acid and haemoglobin (Hb) levels in 100 newly diagnosed primary hypothyroid patients. The same patients were revaluated after treatment with L-thyroxine at the end of six months. Fasting venous sample was used for analyzing the parameters. Statistical analysis was done using student’s unpaired‘t’ test. Pearson’s correlation coefficient test was done to establish the relationships between the parameters. Results: The serum creatinine, uric acid, TC, TG, LDL-Cholesterol, VLDL-Cholesterol were significantly elevated (p<0.001) and HDLCholesterol and Hb levels were significantly decreased (p<0.001) in primary hypothyroid cases. After six months of L-thyroxine treatment, haemoglobin and HDL-cholesterol showed a significant increase (p<0.001), serum TC, TG, LDL-Cholesterol, VLDL-Cholesterol, serum creatinine and serum uric acid levels showed a significant decrease (p<0.001). Conclusion: Thyroid dysfunction induces varied effects on metabolic parameters and early intervention with thyroid replacement therapy resulted in reversible change in the metabolic parameters.</p>