A female prairie rattlesnake (Crotalus viridis viridis) was gastric intubated with 250 tetrathyridia of Mesocestoides sp. The snake was killed 12 wk postinfection; a portion of the liver was examined histologically for evidence of tetrathyridia. Five tetrathyridia were seen in two hepatic portal triad vessels. We propose that a blood-borne metastasis of tetrathyridia in reptiles and rodents may occur.