We have cloned and characterized an antiapoptotic gene, p35, which blocks apoptosis, from Bombyx mori nuclear polyhedrosis virus (BmNPV) K1 strain. The 897 bp p35 has an open reading frame of 299 amino acids. The BmNPV-K1 p35 showed a high identity to Autographa californica nuclear polyhedrosis virus and BmNPV T3 strain. The BmNPV-K1 p35 was different from the amino acid sequences of BmNPV T3 at 6 positions. The p35 gene of BmNPV-K1 was 99.2% identical at the nucleotide level and 98% identical at the amino acid level to BmNPV T3. The location of p35 gene in the BmNPV-K1 genome was confirmed by Southern blot analysis and its expression patterns at the transcriptional level in the infected cells were con- firmed by Northern hybridization analysis.