A full-size cloned cDNA copy of the rotavirus gene encoding the structural neutralization glycoprotein (VP7) of Nebraska calf diarrhea virus (NCDV), a strain recently shown to be effective as a vaccine in children, has been sequenced. Comparison of the deduced amino acid sequence of NCDV (serotype 6) VP7 with that of four other rotavirus strains (human WA serotype 1, human HU-5 serotype 2, simian SA-11 serotype 3, and bovine UK serotype 6) indicates that the degree of amino acid homology among VP7 neutralization proteins of these serotypes ranges from 75 to 86%. Four hydrophilic regions at amino acid residues 174-183, 248-256, 287-294, and 310-317 exhibit significant homology and hence may represent common antigenic determinants, while one hydrophilic area at amino acid residues 83-102 exhibits sufficient divergence to suggest it may be involved in serotype specificity.