The approach to the diagnosis of heart failure is complex, but the diagnostic armamentarium has increased significantly in the past decade. Diagnostic markers such as B-type natriuretic peptide and NT pro-B-type natriuretic peptide have proven value for the diagnosis of heart failure over and above the traditional tools that included only the history, physical examination, and chest radiography. Invasive and noninvasive impedance cardiography can be used to diagnose or even predict development of heart failure, but its role in clinical practice still needs to be better defined.