Aim of this study is to detect the protective role of selenium (Se) against bone marrow and blood toxicity in CP-induced hematoxicity model. We categorized the rats into 6 groups of 7 animals in each group (control; 150 mg/kg CP; 0.5 mg/kg Se; 1 mg/kg Se; 150+0.5 mg/kg CP+Se; 150+1 mg/kg CP+Se). Se injections started 5 days before the CP injections and carried on until the end of the experiment (6th day) for the groups to which CP was injected together with Se. CP was applied as a single dose before anesthesia. For that reason, on the 7th day, blood was taken with cardiac puncture and bone marrow was taken by flushing the femur. Peripheral blood cells and bone marrow nucleated cells were counted on a cell counter. Intraperitoneal CP injection was found to reduce the number of leukocytes by 317%, thrombocyte by 36% and bone marrow nucleated cells by 481% compared to the control group. In the groups where CP was given after 0.5 and 1 mg/kg Se, numbers of leukocyte, thrombocyte and bone marrow nucleated cells were considerably improved compared to the group to which CP was given only (p<0.001). Results show that 1 mg/kg Se has a better protection than 0.5 mg/kg against CP associated hematoxicity and myelosuppression. Our results also imply that the doses of Se could be adjusted according to enhance in CP dose so as to gain a stronger protective effect. We believe there is a need of further studies in which different doses of Se will be used against CP induced hematoxicity. Se can provide protection against CP-induced myelosupression and lipid peroxidation.