Five cases of trophoblastic disease evaluated by gray scale ultrasonography were reviewed. The ultrasonographic findings of trophoblastic disease are discussed and illustrated. Thecalutein cyst is reported to be associated with high levels of human chorionic gonadotropin (HCG). From our limited study, there was no correlation between theca-lutein cyst formation or size and the HCG titers of the patients at the time of examination. Molar evacuation must be followed in correlation with abdominal ultrasound and frequent monitoring of HCG levels.