The present study included 340 inpatients of SMI Hospital admitted during the period January 2014 to December 2014 to study thyroid hormone profile in critically ill patients. The patients with history of thyroid disorders or any family history of thyroid disorders were excluded from the study. Serum free triiodothyronine (fT3), free tetraiodothyronine (fT4) and TSH (Thyroid Stimulating Hormone) levels were assessed in critically ill patients admitted in wards and Intensive Care Units (ICUs). 59% of the critically ill patients admitted in wards and ICUs showed abnormality in one or more than one parameters of the thyroid profile. Low fT3 level was the most common abnormality found in these patients. High TSH and low fT4 levels were the other common abnormalities. Assessment of thyroid function should be carried out in the critically ill patients, only if the clinical suspicion is very high. Otherwise the results may be misleading. The clinicians should consider that abnormal thyroid function test results in critically ill patients are more likely to be due to the alteration in the metabolism of thyroid hormones secondary to the disease process, rather than the thyroid disorder itself.