The aims of study is to determine cytogenetic and genotoxic effect of aflatoxin B1 in vivo, cytogenetic tests are used in studying include chromosome malformation, cell proliferation and plast index test in bone marrow cell in Wight albino rats, the results show that toxin causes Varity in chromosome malformation and increased the rate of it, so it increased in cell proliferation and plast index value compare with negative control