Introduction: DMBA is carcinogenic-immunosuppressant. This study was conducted to investigate the immunosuppressant effect of dimethylbenzanthracene (DMBA) on H-Ras expression, hemogram, and CD8 count I Sprague Dawley (SD) rats. Methods: We divided the test animals into three groups. The normal group received standard food and drink. We induced the DMBA group with 10x20mg/kg BW DMBA for five weeks. The solvent group received standard feeding and corn oil solutions. We conducted dissection and data retrieval in week 27. The immunosuppressant effects of DMBA are measured by number leukocytes and CD8CTL. The number of CD8 is determined by the flow cytometer. The H-Ras gene expression is assessed using densitometry after PCR. The mean intergroup difference was calculated using ANOVA. Result: The results showed that DMBA administration increases H-Ras gene expression and decreases CD8 count (p<0.05). 10x20 mg/kg BW DMBA administration decrease leukocytes and platelet (p<0.05). Conclusion: A dose of 10x20 mg/kg BW DMBA decreased CD8, leukocytes, and platelet number, while it increased H-Ras gene expression in SD rats.