Integrin are adhesion molecules involved in uterine–conceptus interactions during the perimplantation period. In this study, the expression of αV and β3 integrin subunits in endometrium during implantation in pigs was investigated. The immunohistochemical location was performed on paraformaldehyde-fixed, paraffin-embedded tissue sections, and the mRNA expression of αV was detected in endometrium. In addition, serum levels of estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone were measured on Days 0, 12, 18, and 25 of pregnancy. The results indicate that endometrium expressed integrin αV and β3 in all stages examined. The most intensive staining for integrin αV and β3 was observed in endometrial stroma in porcine pregnancy on Day 18. The mRNA of αV integrin strongly expressed on Day 18, and moderately expressed on Days 12 and 25. The correlation between serum hormone level and the mRNA expression of αV integrin was not significant. The expression patterns of integrin αV and β3 during implantation provide insights into the important physiological function of αVβ3 integrin in pig, and the strong expression of integrin αV and β3 in mid-implantation may indicate its crucial role in successful implantation and embryo survival. Mol. Reprod. Dev. 74: 1379–1385, 2007. © 2007 Wiley-Liss, Inc.