OBJECTIVES There is limited evidence of comparative effectiveness of Angiotensin Receptor Blockers(ARBs) for the treatment of Chronic Heart Failure (CHF). We compared the clinical effectiveness of Losartan, Valsartan,Candesartan, Telmisartan and Irbesartan in patients with CHF. METHODS The study was a retrospective cohort study utilizing national Veterans Affairs electronic medical records. The cohort consisted of all heart failure patients diagnosed between October 1, 1997 to September 30, 2002. After excluding patients with any exposure to ARBs within the previous 6 months, new exposure to ARBs was determined between the index date (October 1, 2000) and the study end date (September 30, 2002) and subsequent time to death was measured concurrently during that period. Five treatment groups were defined based on initial use of: Candesartan, Valsartan, Losartan, Irbesartan, and Telmisartan. Multiple Cox proportional hazards regression analysis was employed to assess the adjusted association between these treatments and time to death after controlling for demographics, hospitalization, years with CHF, 30 comorbidities and comedications. Losartan was chosen as the reference drug because it was the first ARB introduced into the market. RESULTS Total 19,186 patients were identified. Majority of the patients were male (98.06%).The most common comorbid condition in the cohort was hypertension(81.17%) followed by Ischemic Heart Disease(68.65%) and diabetes(48.46%). Irbesartan (55.50%) was the most commonly prescribed ARB followed by Losartan (19.44%). In the multivariable model losartan was found to have a statistically significant decreased risk as compared to telmisartan ,adjusted hazard ratio for telmisartan was 1.66 (95% CI: 1.12 – 2.46).Irbesartan, Valsartan, and Candesartan were not statistically significantly different from Losartan. CONCLUSIONS All of the ARBs had similar associations with time to death, except telmisartan, which had a statistically increased risk of mortality within two years. Further research is needed to examine other outcomes including cost-effectiveness in the treatment of heart failure.