A new cell line was derived from the epithelioid sarcoma of a Caucasian woman who had previously received chemotherapy. The cells grew as an adherent monolayer, with a doubling time of 28 hr and had mainly epithelial morphology, but with areas of mesenchymal-like cytoplasmic extensions. The cells were tumorigenic in nude mice, with a short growth time, and a doubling time of 8 days. The cell line showed over-expression of P-glycoprotein by Western blot analysis, and its sensitivity to doxorubicin and vincristine was low. This sensitivity could be enhanced by reversants of multidrug resistance (MDR), such as cyclosporin or verapamil. This cell line constitutes an excellent model for studying compounds able to reverse MDR.