Antipeptide antibodies were elicited against two synthetic peptides corresponding to amino acids 47-55 and 98-103 of the structural protein VP 2 of SV 40. The induced antibodies proved to be VP 2-specific in an immunoblot. In immunofluorescence these antibodies showed a discrete nuclear and perinuclear staining pattern. In immune electron microscopy studies the induced antibodies did not bind to major virions suggesting that VP 2 is not present at the surface of SV 40 particles.