In the country of Morada Nova, State of Ceará, 1.368 Mammal's where searched for T. cruzi and have shown the foilowing results: 443 dogs with 2,5% positives; 605 cats with 0,7% 65 domestic rodents with 4,6%, 6 rabbits and 10 guinea pigs negatives. Among the syivatic animais, 215 rodents "preás" (Galea s. spixii) have shown 2,3% positives, 12 marsupiais (Didelphis azarae) with 9 positive, 5 bats, 5 rodents known as "punaré" (Cercomys c. laurentius) and 3 armadillos (Dasypus novencinctus) negative. The rates shown are sufficient to consider the region surveyed as endemic for Chagas disease and to show the circulation of T. cruzi into domestic and sylvatic cicles.