The prevalence of Toxoplasma gondii in free-ranging chickens can be considered a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 29 free-range chickens ( Gallus domesticus ) from Argentina was investigated. Blood, heart, and brain from each chicken were examined for T. gondii infection. Antibodies to T. gondii , assayed with the modified agglutination test (MAT), were found in 19 of 29 (65.5%) chickens. Hearts and brains of seropositive (MAT ≥ 1:5) chickens were bioassayed in mice. Toxoplasma gondii was isolated from 9 of 19 seropositive chickens. Genotyping of chicken isolates of T. gondii using the SAG2 locus indicated that 1 was type I, 1 was type II, and 7 were type III. This is the first report of isolation of T. gondii from chickens from Argentina.