Lard and lean beef were irradiated separately in a beam of accelerated electrons (6 million rep in a Van de Graaff apparatus). Test meals were fed to dogs, using combinations of irradiated and unirradiated lard and beef. On the average irradiated lard, whether fed by itself or with meat, was retained in the stomach to a greater extent than normal lard (65% vs. 47%), filled the small intestine to a smaller extent (8% vs. 11%), and was less readily absorbed (27% vs. 42%) in a specified time. The difference in absorption can be accounted for by the difference in gastric evacuation. The peroxide value of lard rose abruptly on radiation from 1–2 to 176 and in 14 months of cold storage continued to rise to approximately twice this value. It is concluded that irradiation of lard is detrimental to its digestion in the dog. Submitted on December 22, 1958