The present study aimed to evaluate the immunogenicity of a DNA vaccine encoding rop18-Toxoplasma gondii gene against oocyst shedding in domestic cats. The pcDNA-rop18+ vector under the control of cytomegalovirus enhancer/promoter and intron A was constructed by molecular cloning technique. The antigen expression and immune response were evaluated by inoculation of these recombinant plasmids in cats. Five domestic cats (Felis catus) were divided into two groups G1 (n=3), and G2 (n=2), animals from G1 received 25 μg of pcDNA 3.1+rop18, and G2 received 25 μg of pcDNA 3.1 TOPO (control group), both immunizations were performed by intramuscular route with four doses every 3 weeks plus levamisole(1%). The challenge was performed in all animals on day 93 with 300 tissue cysts of ME49 T. gondii strain by a gastric tube. Animals in all groups had their feces examined and the number of oocysts was determined for 20 days after the challenge. Animals from G1 shed fewer oocysts (≈40% less) than control groups. Elisa was used to detect anti-rROP18 IgG before and after the challenge, despite the statistical difference in antibody response of groups before the challenge, there was no correlation between oocysts shed and antibody levels. In conclusion, there was a perspective to use ROP18 as a vaccine candidate for T. gondii in cats.