Parvovirus B19 (PVB19) has emerged as one of the viruses possibly inducing chronic myocarditis and subsequent idiopathic dilated cardiomyopathy (IDCM). The aim of this work was to investigate the presence and long-term consequences of PVB19-DNA within myocardial biopsies from patients with IDCM and to compare the findings with those from donor hearts (control group). Forty hospitalized IDCM patients (age 47 ± 12 y) with mean left ventricular ejection fraction 27 ± 12% were included. The presence of PVB19-DNA in myocardial biopsies and of IgG and IgM antibodies in patient sera was analyzed. The control group consisted of 20 donor hearts. The follow-up time was 112 ± 57 months. PVB19-DNA was found in myocardial biopsies of both patients (73%) and control samples (55%; P = .25).Three deaths and 8 heart transplantations occurred in the IDCM group, and 6 deaths in the control group (ie, the recipients of the control hearts). No difference in transplantation-free survival between the PVB19-DNA positive/negative IDCM patients or transplant recipients was found. PVB19-DNA is a common finding in both patients with IDCM and in healthy donor hearts, not affecting prognosis. These findings support the view that PVB19 is an innocent bystander, frequently found in myocardium with low DNA copies, and not a plausible cause of IDCM.