Rediae of Echinostoma caproni (Egyptian strain) were dissected from Biomphalaria glabrata snails at intervals from 13-34 days post-exposure and co-cultured for up to 51 days with cells of the B. glabrata embryonic (Bge) cell line. Rediae readily ingested Bge cells and survived longer when co-cultured with cells than in cell-free cultures. Rediae released mostly motile cercariae throughout the observation period when in Bge medium and cells. Rediae cultured in 199 medium with Bge cells also produced progeny throughout most of the observation period. In the latter medium, progeny were much more likely to include rediae as well as cercariae. Some cercariae produced in vitro encysted as metacercariae. Rediae consumed cercariae released into culture but were not observed to attack one another or rediae of a different echinostome species.