The ultrasonographic findings of 49 ovarian cystadenomas were analized. The results were as follows. 1. The most common age group was 3rd decade and most patients(83%) belong to active reproductive period. 2. In 80% of serous cystadenoma the size of the tumor was ranged in 6-10 cm in diameter. The large tumors of 16-20 cm in diameter were mostly mucinous cystadenomas. 3. Purely cystic appearance was the most common findigs(40%) of serous cystadenoma and thick linear septation with and without solid component was the most common findings(38%) of mucious cystadenoma. 4. Thick linerar septation with solid component was not found in serous cystadenoma. 5. Well defined nodular projection was found in 3 cases of serous cystadenoma but not identified in mucinous cystadenoma.