Abstract: Objective : To investigate the effects of 3 -dimensional conformal radiation therapy (3DCRT) combined with chemotherapy and the factors that influence the prognosis in treatment of pancreatic cancer. Methods : Between July 1988 to July 2000, 31 cases of the 64 patients with pancreatic cancer were treated with 3DCRT only, while the other 33 cases with 3DCRT as well as with chemotherapy by Gemcitabine (1000mg/m² , d₁, d₈) and Cisplatin (30mg/m² , d _1~3 ) before and after the radiotherapy with 2 courses. The local control rates of the cancer and the overall 1 -year and 2-year survival rates were noted and the factors that might have influenced the prognosis were analyzed with the Cox regression model. Results : The local control rates were 64.1% and 39.1% respectively at Month 3 and at Month 12. The overall 1-year and 2 -year accumulative survival rates were 40.2% and 6.7 /% respectively, with the median survival time being 11.0 months. The 1-year and 2-year survival rates for patients of Stage I and II were 100.0% and 36.4%, while those for patients of Stage III and IV were 27.4%, 0.0%(P=0.000 1). The 1 -year and 2-year survival rates for the group of only radiotherapy were 28.2% and 4.0%, while those for the group of combined therapy were 51.5% and 9.1% (P=0.041 6 ).The multiple factor analysis showed that the tumor diameter and radiotherapy combined with chemotherapy had statistically significant effects on the survival rate of the patients (P<0.05). Conclusion : 3DCRT combined with chemotherapy to treat pancreatic cancer can obviously improve the life quality and increase the survival rate of the patients, and 3DCRT combined with chemotherapy and the tumor diameter are two major prognosis factors that influence the survival rate of the patients.