Glyphosate herbicide used to control unwanted annual and perennial plants. Roundup, one of the most widely used products containing glyphosate, is classified as hazardous to the environment.  Therefore, this study aim to assess the effect of (25mg/kg) and (50mg/kg) of glyphosate, given to mice by "gavage" and "feeding", by exposure of Cyprinus carpio (Common carp) to the herbicide with the same concentration and then given to mice, and noticeable cytogenetic effects (DNA damage) on mice bone marrow cells (in vivo) by using Comet assay. The statistical analysis shows that glyphosate cause significant increase (P≤0.01) of DNA damage of bone marrow cells in mice in comparing with the negative controls.