ATP-binding cassette super family (ABC) proteins are considered key to oncology and pharmacology studies. We examined the effect of benzene on ABC pump protein levels in C57BL/6 mouse bone marrow mononuclear cells. After a 2-week gavage (200 mg/kg, 5 days per week), the number of peripheral leukocytes, lymphocytes and basophils dropped significantly; there was also a significant decrease in MDR1 and MRP1 gene expression. A significant reduction in expression of P-gp was found; however, there was no significant decrease in the expression of MRP1 and NF-κB p65. We conclude that regulation of membrane efflux transport protein could be a factor in benzene hematotoxicity.