Several pivotal clinical trials have generated new knowledge regarding drug therapy for heart failure. Thus, the Heart Failure Society of America (HFSA) and the American College of Cardiology-American Heart Association (ACC-AHA) guidelines were updated in 2006 and 2005, respectively We review the evidence from these trials and summarize the changes to the HFSA and ACC-AHA guidelines. Based on data from these studies, the new guidelines include broader, stronger recommendations for beta-blocker therapy, and strong recommendations for angiotensin II receptor blockers. The aldosterone antagonists, spironolactone and eplerenone, are also included in the guidelines. Pharmacists should have a basic level of familiarity with the new guidelines on heart failure and the evidence from recent clinical studies. They should be able to relate how this information contributes to the evolving understanding of treatment strategies for heart failure.