Objective: To determine the efficacy of different types of antihypertensive drugs. Study Design: An Observational Study. Place and Duration: In the Medicine Department, Lahore General Hospital, Lahore for the time period of 3 months from July 2017 to September 2017. Materials and methods: These four drugs amlodipine, Irbesartan, captopril, atenolol were administered to patients with hypertension. Four groups were formed, each group consisted of 75 patients, the total number of patients was 300, and working time was up to three months. Blood pressure was recorded after 15 days, 30 days and 60 days. Results: In all groups, blood pressure decreased and Irbesartan result in significant decrease in Blood pressure in patients, drug Irbesartan have much better results than other drugs. Conclusion: According to our analysis, Irbesartan is most effective anti hypertensive drug in controlling Blood pressure than other Hypertensive drugs. However, further studies are needed to reach a real conclusion.