This study attempted to determine the status of tumor suppressor gene p53 in gestational trophoblstic neoplasia. In this study, 19 cases of hydatidiform moles and two choriocarcinoma cell lines(JAR, JEG-3) were evaluated for the presence of alterations of p53 gene. The p53 mutations were evaluated by nonisotopic olymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) and automatic sequencing of PCR products in exons 5, 6, 7, 8. But we could not find any mutations of the p53 gene. This results suggest that p53 mutation maybe rarely involved in the pathogenesis of gestational trophoblastic neoplasia. And nonisotopic SSCP analysis by ethidium bromide staining is considered as an useful method for detecting single base differences in PCR products.