Abstract: Objective: To investigate the imprinting status of IGF- Ⅱgene in renal cell carcinoma and its relationship with the progression of renal cell carcinoma. Methods:Renal cell carcinoma tissues and matched histologically normal kid -ney tissues of30patients were collected. Based on a polymorphism of Apa I site in exon 9 of IGF-Ⅱ, polymerase chain re -action (PCR)-restriction fragment length polymorphism (RFLP) analysis was used to select the heterozygous allele. Loss of imprinting of IGF- Ⅱwas further examined with RT-PCR-PFLP technique. Results: There were19renal cell carcinoma cas -es with heterozygous IGF- Ⅱgene ( 63.3%,19/30). And in these 19case, 13cases had loss of imprinting of IGF-Ⅱgene (68.4%,13/19) in carcinoma tissues and matched histologically normal kidney tissues, and 1 case had loss of imprinting of IGF-Ⅱgene only in carcinoma tissues (5.3%,1/19). Of the 22cases of clear cell renal cell carcinoma, 10cases had loss of imprinting of IGF- Ⅱgene in carcinoma tissues and matched histologically normal kidney tissues ( 45.45%,10/22). Of the 5 cases of papillary renal cell carcinoma, 2 cases had loss of imprinting of IGF- Ⅱgene in carcinoma tissues and matched his tologically normal kidney tissues (40%,2/5). Of the 2 cases of chromophobe renal cell carcinoma, 1 case had loss of im -printing of IGF- Ⅱgene in carcinoma tissues and matched histologically normal kidney tissues. The 1 case of mucinors tubu -lar and spindle cell carcinoma had loss of imprinting of IGF- Ⅱgene only in carcinoma tissues. Of the 8 T1 stage heterozy -gous renal cell carcinoma cases, 6 cases (75%) had loss of imprinting of IGF-Ⅱgene in carcinoma tissues and matched histologically normal kidney tissues, and1 case ( 12.5%) had loss of imprinting of IGF- Ⅱgene only in carcinoma tissues. Conclusion:Loss of imprinting of IGF-Ⅱgene may be an early event of renal cell carcinoma and may play an important role in the development of renal cell carcinoma.