The cardiac hormone brain natriuretic peptide (BNP) plays an important role in the pathophysiology of congestive heart failure (CHF). Studies have established that BNP mediates natriuresis, renin and aldosterone (RAAS) inhibition, vasodilation and lusitropism. Acute cardiac hormone replacement with intravenous infusion of BNP has been shown to possess potent vasodilating actions in humans with acute decompensated CHF resulting in improvement of clinical symptoms. Natrecor (nesiritide) a sterile, purified preparation of human BNP is approved by the FDA for intravenous administration in the treatment of patients with acute decompensated congestive heart failure. However, chronic cardiac hormone replacement with BNP as therapeutic strategy in CHF has been limited by the need to administer BNP intravenously. The objective of this study is to define the cardiorenal and humoral actions of short term (eight weeks) chronic cardiac hormone replacement with subcutaneous (SQ) BNP in human NYHA class II-III CHF. Systolic and diastolic function, left ventricular remodeling as assessed by its volume, renal function, neurohumoral profiling and exercise capacity will be assessed prior to and after eight weeks of treatment.