Abstract: To determine the effective sterilizing dose of ⁶⁰Co-γ ray for rat and mouse feed, the granulated feed was radiated with ⁶⁰Co-γ ray in different doses. The result showed that the effective dose was 25 kGy. The storage term of the radiated feed was at least 90 d. When the feed was radiated with a dose of 30 kGy, its storage term exceeded 180 d. No marked distruction of the nutrients of the radiated feed was found except vitman B₁ which decreased about 20% , while in the autoclaved (121℃, 30 min) feed the crude protein, amino acids and vitmans decreased, especially the vitman B₁ decreased about 50%. The weanling nude mice fed with the radiated feed (25 kGy) for one month grew faster than those fed with the autoclaved feed (P＜0.05).