This investigation was carried out in 10 small towns of the State of Bahia (Northeastern Brazil). The objective was to study the correlations between the prevalences of liver and spleen enlargment in different areas and the prevalence and intensity of Schistosoma mansoni infection in the same areas. Our conclusions are that: a) schistosomiasis mansoni morbidity (prevalences of hepatomegaly and splenomegaly) was directly correlated to the prevalence and intensity of infection; b) the intensity of infection of a community is a good indicator of morbidity and explain the morbidity variation between areas better than the prevalence of infection; c) the prevalence of splenomegaly and the mean size of the liver in the mid-sternal line appear to be good indicators of the S. mansoni prevalence and intensity of infection in a community. Our conclusions raised the possibility of construction of definitive regressions equations between indicators of morbidity and indicators of infection, so that the value of one could be used to predict the other.