Gamma irradiation of Trichinella spiralis-infected pork with a dose of 15 to 30 krad blocks maturation of ingested larvae in the host gut and prevents production of larval progeny. Experiments with freshly-slaughtered (prerigor) hog carcasses indicate that larvae distributed throughout the skeletal muscles have similar radiosensitivities. Neither the age of the encysted muscle larvae nor vacuum packaging of the meat significantly affected this radiosensitivity. Postirradiation holding of irradiated meat leads to little if any recovery of trichina viability. The data indicate that 30 krad cesium-137 gamma radiation can be delivered to split market-weight hog carcasses with acceptable uniformity, and that under all conditions tested such a dose can provide a substantial margin of safety for human consumption of heavily infected meat.