A latex agglutination slide test for Toxoplasma antibodies was used on serum samples collected from various animals (111 cats, 113 dogs, three jackals, 393 sheep, 272 goats, 69 cows) in different parts of Iran. The sero-positive rate in titres 1:2-1:256 in different animals ranged from 12.6 to 56.0%; the highest (56.0%) was found in the stray dogs. Suspensions of the brains of 120 sero-positive animals (17 cats, 14 dogs, one jackal, 66 sheep, 22 goats) as well as 13 sero-negative animals (11 dogs, two jackals) and four black kites (Milvus migrans) not serologically tested were inoculated intraperitoneally into mice for isolation of Toxoplasma gondii. Altogether 16 strains of T. gondii were isolated from cats (47.0%) dogs (14.2%), sheep (7.5%) and a bird (black kite).