From 1990 to 1991, 40 patients with squamous cell carcinoma of the thoracic oesophagus were admitted to our institutions and chemotherapy (oil Bleomycin p.o. and CDDP d.i.v.) either combined with or without hyperthermia was performed, in a prospective randomized trial carried out to investigate the effects of hyperthermia. The two groups (group A, consisting of 20 patients given chemotherapy alone; and group B, made up of 20 given chemotherapy with hyperthermia) were comparable with regard to various prognostic factors. Following the above treatment regimens, an oesophagectomy was done in 16 and 17 patients from groups A and B, respectively. A subjective improvement of dysphagia was seen in 8 (40.0%), and in 14 patients (70.0%), while a radiographic improvement was recognized in 5 (25.0%) and 10 cases (50.0%) in groups A and B, respectively. In the resected specimen of 16 (group A) and 17 patients (group B), histopathological evidence of the effectiveness of the treatments were recognized in 3 (18.8%) and 7 (41.2%) from groups A and B, respectively. Excluding the cases of superficial carcinoma (T1 tumour), histologic effectiveness of the treatments were recognized in 2 (14.3%) and 7 (58.3%) in groups A and B, respectively (p < 0.05). There was no difference in the occurrence of side effects between the groups. Therefore, the clinical and pathological effects were favourable in the hyperthermia combined with chemotherapy group, especially in the cases with advanced oesophageal cancer.