This study aimed to estimate the occurrence of anti-Toxoplasma gondii antibodies by means of the Indirect Immunufluorescent Antibody Assay (IFAT) in cattle and pigs from slaughterhouses in two municipalities in the State of Rio de Janeiro. IgG anti-T. gondii antibodies was found in 1.96% (9/459) of the cattle and 7.64% (31/406) of the pigs, without any positive association (p > 0.05) with risk factors for transmission and seropositivity. Taking the cutoff point of IFAT ³ 1:64, titers of 64 and 256 were detected, suggesting chronic infection. Despite the low prevalence rates found for cattle and pigs, these indicated environmental contamination in the municipalities investigated, biosafety failures at the technified pig farm evaluated and the possibility of human and animal infection through eating raw or undercooked meat from these animals.