The aim of this study is to review some of the ecoepidemiological aspects of american cutaneous leishmaniasis (ACL) in the State of São Paulo, Brazil. During the first half of this century ACL occurred in São Paulo, predominantly on the bank of the Tietê River, where there were railroad constructions and there was inevitable contact between workers and forested areas. Man's activities resulted in a drastic reduction of the forested regions of the State and molded the present landscape found in São Paulo, which brought a gradual change in the epidemiology of ACL during this century. Currently ACL can be considered as an endemic disease. Nowadays, ACL is found in different regions of São Paulo State, and is no longer limited to the bank of the Tietê River. The disease occurs in all age groups and sexes. Lack of knowledge about wild reservoir hosts of Leishmania (V.) braziliensis has simulated speculation about the possible role played by domestic animals (dogs and equines). Man's activities also favoured Lutzomyia intermedia a sandfly species which can clearly thrive in changed environments. L.(V.) braziliensis continues to be transmitted, even after decades of forest destruction in São Paulo.