We report the first complete nucleotide sequence of the picornavirus coxsackievirus B5 (CB5), strain 1954/UK/85, an isolate from a case of hand-foot-and-mouth disease. We have compared the sequence with those of other coxsackie B viruses, coxsackievirus A9, poliovirus and swine vesicular disease virus (SVDV). The genes encoding the three major capsid proteins are most closely related to those of SVDV but the 5' and 3' noncoding regions and the P3 gene are more similar to the corresponding regions in the other coxsackie B viruses than to those of SVDV. These observations are considered in the light of the antigenic and biochemical relationships between SVDV and CB5.