This study reports the survival, hemocyte count and physiological response indicators of pearl oysters Pteria sterna and Pinctada mazatlanica seeded with allografts and xenografts for pearl culture. Two treatments of oysters receiving an allograft (both donor and host were Pt. sterna) or a xenograft (donor was Pt. sterna and host was P. mazatlanica) were compared against two control groups of unseeded oysters (allografts and xenografts) at 0, 0.5, 2, 24, and 72 h. While survival was not affected by any particular treatment, the number of circulating hemocytes was inversely proportional in both species; it did not vary in Pt. sterna after allografting from t0 to 2 h, but then gradually increased and reached a 4-fold peak at 72 h that differed significantly from its control group and t0. In P. mazatlanica, the hemocyte count increased significantly (3-fold) at 0.5 h after xenografting, but then gradually decreased to equal the value of its control group and t0 at 72 h. In Pt. sterna, glycogen and mucopolysaccharide indices decreased >50 % at 2 h and gradually returned to the initial value at 72 h. In contrast, neither index varied significantly in P. mazatlanica, indicating almost no use of energy stores to compensate for the effects of xenografting, as well as little mucus production due to tissue irritation, compared to allografting in Pt. sterna. The lipofuscin index followed a relatively stable pattern over time in treatments A and X and changes with respect to their control groups CA and CX were not significant up to 72 h. Our results indicate that P. mazatlanica responded significantly faster to xenografting and wound healing than Pt. sterna to allografting, and may be a viable host to receive Pt. sterna xenografts. This could contribute to improve pearl yield and quality in Pt. sterna.