Abstract: Objective: To investigate homozygous deletion and mutation of the CDKN2A gene (p16INK4a andp14ARF gene) in 38 hydatidiform mole patients and 30 early pregnancy patients. Methods: A total of 38 hydatidiformmole and 30 early pregnancy villi samples were assessed for homozygous deletion of the CDKN2A gene by polymerasechain reaction (PCR), and mutations were detected using degenerative high performance liquid chromatography (DHPLC). Results: (1) Among the 38 hydatidiform mole samples, homozygous deletions of p16INK4a exon 1 were identified in 5 cas-es (13.16%). However, no homozygous deletions of p16INK4a exon 1 were found in the 30 early pregnancy samples. Asignificant difference was found in the rate of homozygous deletion of p16INK4a exon 1 between hydatidiform mole andearly pregnancy villi samples(P=0.036). (2) No homozygous deletions of p14ARF exon 1 and p16INK4a exon 2 were foundin any of the 38 hydatidiform mole samples or the 30 early pregnancy samples. (3) In all samples, all PCR amplificationproducts of p14ARF exon 1 and p16INK4a exon 1 and 2 produced single peak curves when detected by DHPLC, suggest-ing an absence of mutations. Conclusion: There is probably a close correlation between the homozygous deletion of CD-KN2A and the occurrence of hydatidiform mole.