HKUS cell line was established by culturing a uterine cervical small cell non-keratinizing squamous cell carcinoma from a 70-year-old woman. The cells were spindle-like and roundish in shape and in an epithelial cell arrangement. No contact inhibition was observed, and the cells proliferated in multi-layer fashion. Proliferation was quick and more than 250 passages were observed within 4 years after establishment. The chromosome number mode was found in the diploid range, and the chromosomes of stem cells showed a structure abnormality of 45, X, -X. Most HKUS cells had characteristics of glandular cells, and adenocarcinoma was formed when the cells were transplanted into the subepidermis of nude mouse. Some HKUS cells had characteristics of squamous epithelial cells. The HKUS line is regarded as a primitive carcinoma cell line that can differentiate into squamous cell carcinoma and adenocarcinoma.