Purpose: To evaluate the influence of bioactivation with argon plasma of a xenograft used as graft material for sinus floor augmentation. Materials and Methods: Sinus floor elevation was performed in 20 rabbits using a deproteinized bovine bone mineral as graft material. The xenograft used in the test sites was bioactivated with argon plasma (plasma group), while that used in the control sites was left untreated (control group). Collagen membranes were used to cover the antrostomy. The rabbits were euthanized after 2 and 10 weeks, in groups of 10 each. A histomorphometric analysis was performed in various regions of the elevated space. Results: After 2 weeks of healing, a similar pattern of healing was observed in both groups. New bone fractions were 5.2% ± 2.9% in the plasma group and 5.0% ± 3.5% in the control group (P = .795). In this period, higher amounts of new bone were found in the region close to the sinus bone walls. After 10 weeks of healing, the amounts of new bone within the elevated space increased to 23.5% ± 7.0% and 21.3% ± 7.3% (P = .176) in the plasma and control groups, respectively. The only statistically significant difference was found in the central region, with 20.4% ± 9.7% in the plasma group and 13.2% ± 10.5% in the control group (P = .037). Conclusion: The bioactivation of a xenograft using argon plasma improved bone formation within an augmented sinus, especially in the central regions, far from osteogenic sources. Keywords: animal study, argon plasma, bone healing, sinus floor elevation, xenograft