A 32-year-old woman was admitted with the diagnosis of congestive heart failure (CHF) without organic heart disease after peripheral blood stem cell transplantation (PBSCT) for malignant lymphoma. Various cytokines have been reported to be released from stem cells after PBSCT and some have a suppressive effect on myocardial contractility; elevated levels of cytokines have been reported in dilated cardiomyopathy (DCM) and/or CHF patients. In the present case, elevated levels of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-alpha) were observed, and there was a parallel relationship between the recovery of cardiac function and the decrease of these cytokines, strongly suggesting that the release of IL-6 and TNF-alpha after PBSCT might have been important in the pathogenesis of the CHF.