Subrenal Capsule Assay (SRCA) as a chemosensitivity test was performed on 39 esophageal squamous cell carcinomas in order to select a more effective chemotherapy and assess the correspondence between the assay results and clinical results. The implant grew progressively for six days and decreased from day 7 in the group of control mice. Histologically, host cell infiltration and new vessel was observed from day 3 after transplantation. Tumor growth curve was not influenced by immunosuppression with cyclophosphamide for six days. As primary esophageal squamous cell carcinomas, two diameter method was more sufficient for evaluating the sensitivity than volume method. Macroscopically, the rate of remained implants was 88.2% and yielded an evaluable assay rate of 94.9%. As to sensitivity, the effective rate of CDDP was 24.3%, BLM was 5.9%, MTX was 8.6% and VDS was 20.7%. Histologically, the rate of tumor cells occupied in implant was decreased by grade of augmentation of effectiveness. Clinically, correspondence between the assay results and clinical result was obtained in 92.3%. SRCA is a new promising chemosensitivity test which is clinically useful, and the present results indicated the feasibility of its use in developing an effective chemotherapy for primary esophageal cancer.