The susceptibility of 3 species of snails from, Brazil, B. glabrata (Minas Gerais - MG - and São Paulo - SP - States), B. tenagophila (SP) and B. straminea (SP) to experimental infection with 4 human (MAP, PTH VPH, and OuH) and 2 rodent (PTR and VPR both from SP) isolates of S. mansoni was studied. Snails of each species were exposed individually to 10 miracidia and observed during a 70 day experimental period for mortality, sporocyst development and number of snails shedding cercariae. The B. glabrata from MG -was found to be susceptible to MAP (MG) and 5 from SP (PTH, VPH, OuH, PTR and VPR). The B. glabrata from SP -was found to be susceptible to MAP, OuH and VPR. High mortalites were observed among B. glabrata from SP. The B. stramlnea was found to be susceptible to MAP (only sporocysts), OuH and VPR parasites; mortality rates were lower in this species of snail than in the other species tested. B. tenagophila from SP was found to be susceptible only to sympatric strains, but with low infection rates. The results indicate the importance of transmission of schistosome by human migration from São Paulo to other Brazilian areas.