Background : Aside from enteroviruses, various viruses such as parvovirus B19 (PVB19) may be a new and important candidate for myocarditis and non-ischemic dilated cardiomyopathy (NDCM). There were few studies on the prevalence of viral genomes in Asian population. The purpose of this study was to investigate endomyocardial biopsies (EMBs) from patients with NDCM for the presence of viral genomes by polymerase chain reaction (PCR). Methods : EMBs were obtained from 71 patients with NDCM in Daegu, Korea. Active myocarditis by Dallas criteria was excluded. PCR and reverse transcription-PCR were performed to detect the genomes of enterovirus (EV), adenovirus, PVB19, cytomegalovirus, Epstein-Barr virus, herpes simplex virus (HSV), human herpesvirus 6 (HHV6). EMBs were also assessed by immunohistochemical staining (IHCS) for CD3, CD45, and CD68. Results : Mean age of patients were 51 (range: 17-71) and 43 (61%) were male. Patients with duration of symptoms less than 6 months were 49 (69%). Thirty (43%) of the 71 EMB were positive to viral genomes: EV = 1 (1.4%), PVB19 = 24 (33.8%), HHV6 = 4 (5.6%), CMV = 2 (2.8%), HSV2 = 1 (1.4%), including 2 case with multiple infection (PVB19+HHV6, PVB19+CMV) (Figure). Twenty-four (59%) of 41 EMBs without viral genomes and 21 (70%) of 30 EMBs with viral genomes were positive to IHCS for cellular or adhesion makers. There were no differences in initial echocardiographic parameters and clinical event rates during short-term follow-up between two groups. Conclusion : Forty-three percent of EMB were positive to viral genomes by PCR. PVB19 genome was most frequently detected in EMBs of patients with NDCM in this population.