Amlodipine is the commonly used Calcium channel blocker. Calcium channel blockers are known to intervene with functioning of various hormonal systems. Hypothyroidism is a commonly prevailing disorder in adult Indian population. Knowledge on Drug induced hypothyroidism, though not a major cause of hypothyroidism, holds an important role in preventing the iatrogenic introduction of disease. This study was taken up to observe the effects of Amlodipine on long term usage in hypertensive patients. A comparative prospective observational study carried out in medical outpatient department in Osmania General Hospital, Hyderabad, for a duration of 6 months showed a significant decrease in T3 and T4 levels and increase in TSH levels. Calcium channel blockers, in particular Amlodipine caused significant increase in TSH and decrease in T3, T4 hormones on administration for a period of 6 months in comparison to Enalapril.