Chagas's disease is known to the scientific world since 1909. Due to its clinical particuliarities, evidence of its occurrence and distribution prior to 1909 is fragmentary. However, a careful analysis of medical and non-medical writings of the 19th century enables us to draw some conclusions of the epidemiology of the disease in Brazil, and particulary in the State of São Paulo. Possibly, acess to rare books on colonial and imperial Brazil will throw more light on the subject.