In the present study, the case of a 34-year-old Chinese female who underwent in vitro fertilization resulting in a twin pregnancy was reported. Following in vitro fertilization, the patient was found to have a partial hydatidiform mole (PHM) with a co-existing twin by transvaginal sonography (TVS). At 16 weeks, the pregnancy was terminated and a normal-looking fetus with a HM placenta was delivered, in addition to a normal fetus with a normal placenta. Following termination of the pregnancy, the PHM progressed into an invasive mole with lung metastasis, a rare event. Serum human chorionic gonadotrophin (hCG) concentrations decreased in the first week following delivery, but over the following 21 days hCG levels showed a continuous increase. Following 2 cycles of combinative chemotherapy consisting of fluorouracil (5-FU) and dactinomycin (KSM), hCG concentrations decreased to normal levels. The patient was then administered 1 cycle of repeated chemotherapy and hCG levels remained negative for the following 2 years.