The aim of this study was to investigate viral etiology in dilated cardiomyopathy (DCM) by polymerase chain reaction (PCR) or nested reverse tanscription PCR (RT-PCR), and characterize the enteroviral RNA presented in the clinical specimens. Twenty-eight paraffin-embedded heart tissue samples were assayed to detect cytomegalovirus, herpes simplex virus type 1, type 2, parvovirus, adenovirus, and enterovirus (EV) with each specific primer. Of these 28 patients (mean age: 27, M: 24, F: 4), 26 were histologically diagnosed as DCM and 2 as myocardial infarction (MI). Nested RT-PCR detected enteroviral RNA in 7 (26.9%) of 26 patients with DCM, and none of patients with MI. And none of DNA viruses tested were detected from the samples. Amplified products were also genotyped by single-variation of EV is present in the explanted heart tissues from patients with DCM. Although most of the sequences among the wild isolates have the greatest similarity to those of coxsackievirus B3, there are specific regions of variable sequences (no 490 - no 510). The data suggest that enterovirus may be a major viral pathogen for the DCM in Korea and nucleotide sequence data indicate that coxsackievirus B3 may be a leading etiologic agent of DCM.