During the last years, our knowledge on the pathophysiology and therapy of congestive heart failure has experienced a great growth. The goals of the therapy for heart failure have changed since new drugs have demonstrated to increase survival as well as to improve symptoms and functional capacity in patients with this syndrome. It has also been shown that therapeutic intervention can prevent the development of heart failure and decrease long-term mortality in patients with asymptomatic left ventricular dysfunction. In this article, we have reviewed the results from the most important clinical trials carried out during the last years in patients with overt congestive heart failure and asymptomatic left ventricular dysfunction with several drugs (digitalis, diuretics, angiotension-converting-enzyme inhibitors, other vasodilators, calcium-antagonists, non-glycoside inotropics antiarrhythmics, etc.). Nevertheless, in spite of this impressive increase in the knowledge on heart failure, some important questions remain unanswered.