We used a new method of deoxyribonucleic acid fingerprint analysis to obtain the differential diagnosis between complete mole and hydropic abortus. This method with a deoxyribonucleic acid minisatellite probe requires only a small amount of tissue sample and peripheral blood, and presents individual specific restriction fragment length polymorphisms (deoxyribonucleic acid "fingerprints") by simultaneous detection of many hypervariable regions (minisatellite regions) widely dispersed in the human genome. Southern blot hybridization showed that in cases of complete mole, all polymorphic fragments were exclusively inherited from the father. Some of the polymorphic bands of paternal deoxyribonucleic acid were not observed in molar deoxyribonucleic acid. However, in the hydropic abortus, the polymorphic fragments could be traced back to its parent. These results indicate that deoxyribonucleic acid fingerprints could distinguish the abnormal fertilization of complete mole (androgenesis) from the normal fertilization of hydropic abortus by identifying the difference in genetic variations between complete mole and hydropic abortus at the deoxyribonucleic acid level.