Abstract: Objective 　To evaluate the predictive effect of the thymidylate synthase mRNA level to the response of the chemotherapy with cisplatin and fluorouracil in unt reated esophageal cancer by detecting the thymidylate synthase. Methods 　20 patients with unt reated esophageal cancer accepted two cycles combined chemotherapy with cisplatin and 5-fluorouracil. cisplatin 15～20mg/ m2 >>/ d was int ravenously infused in consecutive five days and 52fluorouracil 375～500 mg/ m2>> / d was int ravenously infused for eight hours per day in consecutive five days per cycle, there were four weeks gap between two cycles. β-actin was used as a internal reference gene and the mRNA level of TS/β-actin in esophageal cancer tissue was determined by semi-quantitative reverse-transcription polymerase chain reaction (RT2PCR) . Data was analysed by Wilcoxon rank sum test in SPSS 10. 0 statistical program. There was a statistical significance, when P< 0. 05 occurred with two2sided test . Results 　For 20 untreated esophageal cancer patient s, the median of TS mRNA level from 11 responding patients was higher than that of 9 nonresponding patients. There was a significant difference between the two groups (Wilcoxon rank sum test, P < 0. 05) . Conclusion 　The TS mRNA level has a certain predictive value to the efficacy of chemotherapy with cisplatin and fluorouracil in esophageal cancer.