Multiple pregnancies with hydatidiform mole are rare. We describe here a patient who delivered a male fetus and a female fetus together with molar tissue following treatment for infertility. comparing microsatellite polymorphisms in the DNA from the patient, her partner, the two normal placentas and the molar tissue, we were able to show that this was a triplet pregnancy with two normal conceptions and a complete hydatidiform mole of monospermic origin.