A growing body of literature describes diagnostic and prognostic value of B-type natriuretic peptides (BNP) in cardiac diseases since it was first described in 1988. As BNP is mainly secreted in the left ventricular (LV) myocardium, BNP was found to reflect LV function much better than any other neurohumoral factor. Thus, BNP is recommended as the first noninvasive blood test for determination of cardiac function by some authors. The introduction of fully automated, rapid bioassays for measurement of BNP and the aminoterminal part of its pro-hormone (NT-pro-BNP) made it possible to use the test even in emergency care settings. Here we review the literature with special focus on assessment of BNP and NT-pro-BNP in the following clinical settings: community screening for LV dysfunction, primary diagnosis of heart failure in general practice and emergency department (ED) and risk stratification in cardiac dysfunction and acute coronary syndromes. In addition, we discuss which applications can be recommended for daily clinical use from the cardiologist's point of view.