We have determined 4380 bases of the sequence from a cDNA clone containing the 3' end of feline calicivirus strain F9. We find four candidate open reading frames of which three are complete and comprise 245, 317 and 2012 nucleotides. The fourth continues toward the 5' end. We have expressed the largest complete open reading frame in E. coli. Sera raised to this antigen react specifically with the capsid protein and its intracellular precursor molecule. N-terminal sequence analysis of purified, mature capsid protein confirms this assignment and has identified the position at which precursor is cleaved.