The dye test for toxoplasmosis was performed on blood samples from 50 foxes, 50 cats, 35 sheep, 432 pigs, and 40 rabbits collected in the area of Siena, Italy. All the animals were apparently healthy, except for 19 rabbits obtained from an epizootic focus. Isolation trials were performed from dye-test positive animals. The incidence of toxoplasmosis was remarkable. A higher number of positive isolations was obtained from animals with higher dye-test titers. Better results in isolation trials could be observed by pooling the inocula from animals with low titers. Numerous strains of Toxoplasma were found in pigs' diaphragms, which are used in Siena as an ingredient of raw sausages. In foxes, cats, and pigs the skeletal muscle appeared to be an important site of cysts in chronic infection. In the rabbit a small epizootic focus was observed, including one instance of generalized asymptomatic toxoplasmosis. A natural congenital transmission is very likely to have occurred in another case.