The results of this study describe the immunostimulatory properties of Leishmania infantum Hsp83 (83) to elicit humoral and cellular response against the Toxoplasma gondii Rop2 protein in an adjuvant-free vaccination system. The analysis was performed by immunizing three different mice strains (BALB/c, C57BL/6 and C3H). Mice immunized with fusion Rop2-83 elicited a stronger humoral and cellular response in comparison to mice immunized with Rop2 alone, or a mix of LiHsp83 and Rop2. The fusion protein induced a Th1 type response, with predominance of specific IgG2a/IgG2c isotype and IFN-gamma secretions, whereas Rop2 alone or mixed with LiHsp83 produced a Th1/Th2 mixed response. Vaccination with fusion protein conferred a remarkable resistance against oral infection with ME49 cysts in C57BL/6 and C3H mice, in comparison to mice immunized with Rop2 alone or the protein mixture. Following lethal challenge, a significant survival rate was observed in Rop2-83 immunized Balb/c and C57BL/6 mice in comparison to control groups.