Objective：To detect the expressions of P-glycoprotein（P-gp） in pediatric Hodgkin disease（HL），non-Hodgkin disease（NHL） and Wilms’ tumor（WT） and to provide theoretical basis for individual chemotherapy in clinics. Methods：Immunohistochem－istry was performed to detect the expressions of P-gp in pediatric tumors（26 cases of HL，24 cases of NHL and 32 cases of WT） and relationship between expressions of P-gp and clinical characteristics of tumors was evaluated. Results：（1）Positive expression rates of P-gp were 57.7%，70.8%，65.6% in HL，NHL and WT. （2）There was no significant difference in P-gp expressions between HL and NHL（P=0.39），between WT and adjacent normal tissues（P=1.00）. （3）Positive expression of P-gp was closely related with lactate dehydrogenase，lymphnode metastasis in HL（P=0.03，P=0.05） and was related with clinical stages in NHL（P=0.02）. There was no significant correlation between expressions of P-gp and histological type，clinical stage，lymphnode metastasis and preoperative chemotherapy of WT. Conclusions：（1）High positive expression of P-gp correlates with tumor resistant of HL，NHL and WT and is one of the unfavorable factors for prognosis. （2）According to expressions of tumor resistant protein，we can better chose chemotherapy drugs in clinics and make children with tumor use sensitive drug.