An adenocarcinoma cell line was established from pleural effusion of a 67-year-old woman and designated as TK-SA. The population doubling time of the cells was 100.4 hr. Chromosomal analysis revealed the TK-SA to have human aneuploid chromosomes with a near-triploid mode. Ultrastructurally, the TK-SA was compatible with adenocarcinoma. The cell line was highly tumorigenic. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide dye assay demonstrated resistance of the cell line to Cis-platin (CDDP), Cyclophosphamide (CPM) and Tegafur/Uracil (UFT). High carcinoembryonic antigen (CEA) and CA19-9 levels were similar in patient's serum and conditioned medium.