We report the characterization of six new gastric carcinoma cell lines (designated NCC-19, NCC-20, NCC-24, NCC-59, SNU-1750 and SNU-1967) established from primary tumor samples of Korean patients. Four cell lines grew as adherent monolayers, one as both adherent and floating cell clumps and one as floating cell aggregates. The cell phenotypes, including the histopathology of the primary tumors and in vitro growth characteristics, were determined. We also performed molecular characterization, including DNA fingerprinting analysis and abnormalities of K-ras, p53, β-catenin, and TGF-βRII genes by PCR-SSCP and sequencing analyses. Population doubling times varied from 47-135 h. All cell lines showed relatively high viability, absence of mycoplasma or bacteria contamination and genetic heterogeneity by DNA fingerprinting analysis. Three lines had p53 mutations; one line had mutations in codon 13 (Gly13Asp) in K-ras and no line had a β-catenin mutation. NCC-59 cell line had a -1-bp mutation in 10-bp poly deoxy adenine repeat tract of the TGF-βRII gene. Moreover, NCC-24 gastric cancer cell line was found to be infected with Epstein-Barr virus (EBV). EBV infection was also shown in the original carcinoma tissue of the NCC-24 cell line. These well-characterized six gastric cancer cell lines should serve as useful tools for investigating the biological characteristics of gastric cancer and, in particular, NCC-24 may serve as a valuable model system to clarify the precise role of EBV in gastric carcinogenesis.