Whether Bombyx mori nuclear polyhedrosis virus (BmNPV) can be transmitted to offspring, has been a noticeable question for a long time. When fifth instar larvae of the silkworm were orally inoculated with BmNPV dot hybridization and PCR amplification analysis demonstrated that BmNPV was not detected in the eggs laid by BmNPV productively infected female moths. The results indicated that BmNPV could not be transovarially transmitted.