Envenomation from pit vipers native to North America can be treated successfully with either of the 2 commercially available antivenoms licensed in the United States. However, envenomations from imported snakes held in zoos or private collections often pose unique challenges to management because of the lack of specific antivenom and the unclear efficacy of the available licensed products. We report the case of a 37-year-old man who was envenomated on his left hand by his pet hognosed viper (Porthidium nasutum ). He had swelling at the wound site that progressively worsened over 3 to 4 hours. His symptom progression included the structural motor impairment of his fingers and a sensory deficit. Treatment with 8 vials of Antivenin (Crotalidae) polyvalent was associated with a halt of extremity swelling and restoration of neurologic and motor function of his hand. Limited experimental evidence provides support for antigenic cross-reactivity between Antivenin (Crotalidae) polyvalent and P nasutum venom.