Renal function is influenced by thyroid status. Therefore, this study was done to determine the relationship between renal function and different degrees of thyroid dysfunction. Thyroid and kidney function tests were analyzed in 47 patients with overt (TSH ≥ 10.0 μIU/L) and 77 patients with subclinical hypothyroidism (TSH 6.0-9.9 μIU/L) in a cross-sectional study. These were compared with 120 age- and sex-matched euthyroid controls. Overt hypothyroid subjects showed significantly raised serum urea, creatinine and uric acid levels as compared to controls whereas subclinical hypothyroid patients showed significant increased levels of serum urea and creatinine levels. TSH showed significant positive correlation with creatinine and uric acid values and, fT4 had a negative correlation with uric acid in overt hypothyroidism. Hypothyroid state is associated with significant derangement in biochemical parameters of renal function. Hence the renal function should be regularly monitored in hypothyroid patients. Copyright © 2011. Published by Elsevier Inc.