Ascitic fluid was obtained from the patient of ovarian endometrioid cancer. Collected cells were incubated with Eagle's MEM containing 15% fetal calf serum at 37 degrees C under humidified 5% CO2 and 95% air. The epithelial colonies grew rapidly and were released without fibroblast cells. After the first passage, the cells are growing without interruption for over one year and 35 transfer generations. This cell line has following charactors: 1) The monolayer cultured cells appeared epithelial, pavement like arrangement and piling up, without contact inhibition. 2) In the cytoplasma PAS positive substance can be seen. 3) Desmosome-like structure, gap junction, microvilli and well developed cell organelles can be found by electron microscopy. 4) Chromosomal number shows pseudodiploidy which mode is 47. A submetacentric chromosome was present in all karyotype and identified by G-banding. It consists of No. 11 and a part of No. 1. 5) By heterotransplantation to the nude athymic mouse, the tumor easily develops. 6) By estradiol and promegestone its growth was inhibited. 7) Estrogen and progesterone receptors were not detected in the cytosol.