We investigated B-type natriuretic peptide (BNP) levels in 10 consecutive patients (all women, mean age 60.4+/-7.8 years) with apical ballooning syndrome. Mean baseline plasma BNP level was 272.6+/-170.4 pg/ml and exceeded the normal range in 8 (80%) patients. When normal levels were adjusted for age and gender, all 10 patients had elevated BNP. Two patients with the highest BNP levels (630 and 423 pg/ml) presented with significant hemodynamic compromise. BNP levels correlated negatively with left ventricular ejection fraction. Increase in BNP levels in apical ballooning syndrome may support the neurohormonal etiology in these patients and requires further studies.