Fourteen synthetic peptides corresponding to previously mapped antigenic sites in VP2 of canine parvovirus (CPV) were used for immunization of rabbits to identify antiviral properties favourable for inclusion into a vaccine. Most antipeptide antisera obtained were reactive with viral protein, and with one of them it was possible to locate the hypothetical amino terminus of VP3 within positions 15-31 of VP2. Virus-neutralizing antibodies were only obtained with two overlapping 15-mer peptides corresponding in sequence to the amino terminus of VP2 (MSDGAVQPDGGQPAVRNERAT). Antibodies in the neutralizing sera bound most strongly to amino acids of the sequence DGGQPAV within the N-terminus of VP2, indicating that efforts to develop a synthetic vaccine against CVP should be focused on this stretch of amino acids. The two peptides induced long-lasting immunity (at least 8 months) using either Freund's adjuvant or aluminium hydroxide plus Quil A. Thus, this approach delineated the exact peptide sequence useful for vaccines applied to the amino-terminal region of VP2. These findings in experimental animals form a solid basis for exploration of a synthetic peptide vaccine against parvovirus infection in dogs, minks or cats.