OBJECTIVE To establish a CDDP-resistant cell line from human tongue squamous cell carcinoma cell line Tca8113 and to study the characteristics of this cell line. METHODS The concentration of CDDP added to Tca8113 cells was increased gradually and the chemotherapeutic drug was added continually, which was to induce the CDDP resistance in Tca8113 cells. The doubling time of Tca8113/CDDP cell line and the oncogenicity of this cell line in nude mice indicated its change on CDDP resistance. The sensibility to drugs of the cell line was assayed by MTT method. DNA fragmentation was detected by electrophoresis. Immunocytochemistry was utilized to examine the expression of P-gp and GST-pi. RESULTS Tca8113 /CDDP was established and the cells grew steadily in 10 micromol/L CDDP medium. The Tca8113/CDDP cells were also resistant to Vm-26, BLM, VDS, E-ADM, Taxol and other drugs in different degrees. The doubling time of the cells was 29.9 hours and after a month it changed to 16.7 hours. When inoculated in nude mice, the cells showed the typical features of squamous cell carcinoma ultra-structurally and pathologically. Agarose gel electrophoresis of DNA from Tca8113 cells treated with CDDP revealed "ladder"pattern, which was the symbol of apoptosis, but there was no "ladder" in Tca8113/CDDP. The expression of P-gp and GST-pi in Tca8113/CDDP was much higher than that in Tca8113, which was the proof of the up-regulating translation of MDR-1 mRNA. CONCLUSIONS CDDP induced Tca8113 cells resistance, and resistant cell line Tca8113/CDDP was established. The multi-drug resistance of Tca8113/CDDP cells were related to the GSH/GST system.