The chromosome aberrations in sperm of mouse induced by various doses of ,60,Co γ rays irradiation and the dose-response relationship were investigated with technique of in vive fertilization and chromosome preparation in the first cleavage metaphase after fertilization. The chromosome aberrations in sperms and in bone marrow cells were compared. Male ICR mouse were irradiated with various dose ,60,Co ,γ, rays. One week after exposure the male were mated with female and chromosome in the first cleavage metaphase were prepared. Chromosome aberrations were analysed and compared in light of radiosensitivity in sperms and marrow cells. The results shows that ,60,Co ,γ, ray induced chromosome aberrations in sperms and the frequencies of chromosome aberrasions increased with the doses. The positive correlation was observed between them, which fitted well to linear regression equation Y=- 4.1636+ 8.3989 D. Frequencies of aberrate sperms and doses fitted well to the equation Y= -0.6215 + 5.331 D. The type of chromosome aderrations observed were mainly the chromosome-type aberration(93.2%). The fragments were predominant in chromosome-type aberration(79.8%). As for the chromosome aberration of sperm and bone marrow cells, the frequencies of total chromosome aberrations and translocations in sperms were obviously higher than that in bone marrow cells. Significant difference was found between them.