Echoviruses are the largest enterovirus subgroup consisting of 32 serotypes. They are common human pathogens causing, for example, meningitis, encephalitis and exanthema, but in spite of their clinical importance, relatively little is known about their biology. To illuminate the molecular characteristics of echoviruses, we have completed the genomic sequence of serotype 11. The RNA genome is 7438 nucleotides in length and it codes for a 2195 amino acid long polyprotein. When compared to other sequenced enteroviruses, echovirus 11 (EV11) shows remarkable similarity with coxsackie B viruses (CBVs) and coxsackievirus A9 (CAV9). On the basis of amino acid sequence homology in the capsid region, CAV9 is the virus most closely related to EV11. These two viruses have an apparent insertion sequence located at the C-terminus of the VP1 polypeptide. EV11, however, lacks the RGD motif found in the corresponding region of CAV9. The organization of the 5' end noncoding region resembles that of other enteroviruses, but contains a 12 nucleotides long poly-U stretch not seen in any other enterovirus sequenced to date.