AbstractTwo heat treatments were carried out at below (Ti6Al4V800) and above (Ti6Al4V1050) the beta-phase transformation temperature (TTRANSUS = 980 °C), to study the effect of microstructural changes on osseointegration. The alloys were implanted in the femurs of hind legs of Wistar rats for 15, 30, and 60 days. Histology of the femur sections obtained for the first 15 days showed inflammatory tissue surrounding the implants and tissue contraction, which prevented osseointegration in early stages. After 30 days, trabecular bone, reduction of inflammatory tissue around the implants, and osseointegration were observed in Ti6Al4V as received and Ti6Al4V1050 alloys, while osseointegration was detected for the three alloys after 60 days. These results were supported through morphometric studies based on the analysis of Bone Implant Contact (BIC), where there was a larger bone contact after 60 days for the Ti6Al4V1050 alloy; indicating that microstructural features of the Ti6Al4V alloys influence their osseointegration, with the lamellar microstructure (Ti6Al4V1050), being the most responsive.