This study aimed to identify the environmental and social factors that determined occurrences of American cutaneous leishmaniasis in the Ribeira valley region of the State of São Paulo between 1998 and 2006.Secondary public-domain data from the 23 municipalities forming this region were used. The study period was divided into three ranges based on the graphical characteristics of the incidence coefficients. These data were subjected to analysis using multiple linear regression.Over the period 1998 to 2000, the variables correlated with American cutaneous leishmaniasis were mean human development index (p = 0.007), per capita income (p = 0.390) and degree of urbanization (p = 0.079). Over the periods 2001 to 2003 and 2004 to 2006, the variables correlated with American cutaneous leishmaniasis were the presence of sandflies (p = 0.000; p = 0.001) and mean urban population (p = 0.007; p = 0.001).These data show the trend towards urbanization and impoverishment of the disease.