PURPOSE: It is known that the wild-type p53 (w-p53) gene has several functions such as suppression of tumor cell growth, control of the cell cycle, stabilization of the genes and cellular differentiation. Recombinant w-p53 adenovirus was transfected and 5-FU was administered into the LoVo (w-p53 gene positive) and SW-837 (mutant-p53 gene positive) colon cancer cell lines to determine the cell death effects according to the presence or absence of the w-p53 gene. METHODS: The transduction of the p53 gene was done using recombinant adenovirus and liposomes, and the cell death effect was determined by performing MTT assay. RESULTS: The cell death effect by 5-FU was higher in the LoVo cell line than that in the SW-837 cell line. The rate of w-p53 gene transduction was about 90%. The cell death effect by w-p53 gene transduction was shown by the administration of 10 microM of 5-FU. The cell death effect according to the administration of 5-FU after w-p53 gene transduction was 10 fold of that with 5-FU administration in the both cell lines, and there was a more significant effect in the LoVo cell line. CONCLUSION: The cell killing effect by 5-FU administration after w-p53 gene transduction showed a synergistically higher effect than those of w-p53 transduction only or 5-FU administration only in the colon cancer cell lines. Gene therapy using w-p53 gene transduction requires more extensive clinical trials.