Abstract: In the present paper,karyotype of the mouse ascites hepatoma is analysed with several banding techniques.The results show that the mouse ascites hepatoma is near-diploid with a modal number of 42-43 (13.0-32.0%) and four or five marker chromosomes.By Ag-As procedure,silver stained NORs (Ag-NORs) are visualized as black spherical bodies on 2-3 chromosomes in the karyotype of the mouse ascites hepatoma.Ag-NORs in this mouse ascites hepatoma cell are usually seen to occur at secondary constrictions on the M1 and M3 chromosomes.