To facilitate studies of the phylogenetic relationship between enteroviruses, in particular the prototype strain (Faulkner) of coxsackievirus B5 (CVB5F) and other CVB5 isolates and to facilitate studies of the interactions between CVB5F and the target cell, the complete nucleotide sequence of the prototype has been determined. The complete sequence was collected from three overlapping reverse transcription polymerase chain reaction (RT-PCR) generated amplicons. Molecular analysis of the CVB5F genome verified that this strain is more related to other CVB5 isolates and to swine vesicular disease virus strains than to other enteroviruses. In addition, comparison of the amino acid sequence derived from the structural genes indicated a division of group B coxsackievirus into subgroups, where CVB1, CVB3 and CVB5 constitute one group, CVB2 and CVB4 from a second group and CVB6 prototype forms a branch of its own. This observation, supported by reports describing the interactions between CVB and the cell surface, may reflect that these subgroups of group B coxsackieviruses have evolved to use slightly different approaches to carry out the complete infectious cycle within the cell.