The acidic glycoprotein gp67 (syn.: gp64) is the most abundant envelope surface glycoprotein of the Autographa californica nuclear polyhedrosis virus (AcNPV baculovirus), and is essential for the entry of baculovirus particles into susceptible insect cells. Since large amounts of this protein are secreted and anchored to the virus peplomer, its gene contains one of the most effective baculovirus-encoded signal sequences for protein secretion. Therefore, we have constructed baculovirus transfer vectors that contain the gp67 signal sequence in front of a multiple cloning site. A gene of choice can be inserted in one of these cloning sites and the protein of interest will be expressed as a gp67 signal peptide fusion protein under the control of the strong baculovirus polyhedrin promoter. This strategy allows the forced secretion of otherwise non-secreted recombinant proteins which may be easily purified when serum-free insect culture medium, BD BaculoGold Max-XP Insect Cell Medium is used. The transfer vector(s) should be preferentially used in conjunction with BD BaculoGold DNA .