Fertilization in mammals requires the successful completion of a sequence of steps, starting with the transport of gametes in the reproductive tract and ending with sperm-egg membrane fusion to produce a zygote. Although some integrin subunits are known to be associated with the plasma membrane of some mammalian oocytes and spermatozoa, the presence of α₆ integrin on bovine oocytes with intact zona pellucida has not been reported. The present study was undertaken to evaluate the expression of α₆ integrin subunit in bovine oocyte and to determine if in vitro binding to the zona pellucida and fertilization were affected by treating oocytes with α₆ integrin subunit antibody. The α₆ integrin subunit was identified on the bovine oocyte by immunocytochemistry. In vitro fertilization was significantly decreased when in vitro matured bovine oocytes were pre-incubated with α₆ integrin subunit antibody at concentration 5 and 20 μg/mL, and spermoocyte binding increased. These studies demonstrated the presence of α₆ integrin subunit on bovine oocyte, and its importance in fertilization and polyspermy.