Even though ultrasonography is a primary tool for evaluation of gynecological pelvic mass, CT can be helpful when ultrasonography is suboptimal either because of abundant intestinal gas or marked obesity. Authors experienced 3 cases of hydatidiform mole demonstrated by cT. The findings of hydatidi-form mole are enlargement of uterus, low density int he uterine cavity, irregular soft tissue mass with small multiple cysts, and strong contrast enhancement of the soft tissue mass within the uterine cavity. CT can be a useful diagnostic tool for differentiation of hydatidiform mole from choriocarcinoma because of good visualization of uterine wall and pelvic structures.