The aim of the present study was to compare the development of Echinostoma caproni (Trematoda: Echinostomatidae) adults in two host species displaying different degrees of compatibility with this parasite. For this purpose, the variability in the worm recovery, egg output, and morphology of E. caproni adults during the course of experimental infections in hamsters and rats was analyzed. Student's t-tests and two-factor ANOVA analysis with the time post-infection and the host species as independent variables, and Bonferroni t-tests as post hoc analysis were used for the study. Worm recovery and egg output were host species dependent. The values were significantly higher in the worms established in hamsters than those in rats. The oral sucker area, pre-pharynx length, and pharynx area were the most conservative features, and no significant variability related to the host species was detected. In contrast, body area, collar width, esophagus length, cirrus sac area, ventral sucker area, ovarian area and anterior and posterior testicular areas were significantly higher in those worms collected from hamsters. Moreover, significant worm age-host species interactions were found for body area, ovarian area, ventral sucker area, and anterior and posterior testicular areas.