Abstract： Objective To study the correlation between ABO blood groups and leukemia and lymphoma, and the regional difference. Methods A case-control study had been conducted. The distribution of ABO blood groups was investigated in leukemia patients, lymphoma patients and controls, respectively. Also ABO blood group distribution of leukemia and lymphoma were compared in different areas. Results The distribution of ABO blood groups between patients with acute non-lymphocytic leukemia, acute lymphocytic leukemia, non-Hodgkin lymphoma and health person was significantly different (χ2 = 21.23, χ2 =8.36, χ2 = 9.39,P <0.05). There were regional differences in the ABO blood groups distribution of leukemia and lymphoma,especially ABO blood groups were significantly different in leukemia patients (χ2 = 50.65, P <0.05).Conclusion ABO blood groups might be a genetic susceptible factor of leukemia and lymphoma, but the geography might be a major influential factor.