Waon therapy (WT), which in Japanese means soothing warmth, is a repeated sauna therapy that improves cardiac and vascular endothelial function in patients with chronic heart failure (CHF). We investigated whether WT could improve the quality of life (QOL) of CHF patients in addition to improving cardiac function and exercise capacity.A total of 49 CHF patients (69 ± 14 years old) were treated with a 60°C far infrared-ray dry sauna bath for 15 minutes and then kept in a bed covered with blankets for 30 minutes once a day for 3 weeks. At baseline and 3 weeks after starting WT, cardiac function, 6-minute walk distance (6MWD), flow mediated dilation (FMD) of the brachial artery, and SF36-QOL scores were determined.WT significantly improved left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP), 6MWD, and FMD (3.6 ± 2.3 to 5.1 ± 2.8%, P < 0.01). Moreover, WT significantly improved not only the physical (PC) but also mental component (MC) of the QOL scores. WT-induced improvement of PC was negatively correlated with changes in BNP (r = -0.327, P < 0.05), but MC improvement was not related directly to changes in BNP, LVEF, or 6MWD. WT-induced changes in MC were not parallel to PC improvement.WT improved QOL as well as cardiac function and exercise capacity in patients with CHF. Mental QOL improved independently of WT-induced improvement of cardiac function and exercise capacity.