Influenza viruses A and B cause widespread infections of the human respiratory tract; however, existing vaccines and drug therapy are of limited value for their treatment. Here, we show that bispecific short-hairpin small-interfering RNA constructs containing an 8-nucleotide intervening spacer, targeted against influenza virus A or influenza virus B, can inhibit the production of both types of virus in infected cell lines. This multiple vector showed remarkable ability to cope with both influenza viruses A and B. Furthermore, the Autographa californica multiple nuclear polyhedrosis virus can infect a range of mammalian cells, facilitating its use as a baculovirus vector for gene delivery into cells. In this study, baculovirus-mediated bispecific short-hairpin RNA expression markedly inhibited both influenza viruses A and B production.