To prevent postoperative local recurrence of rectal cancer, we treated patients using preoperative hyperthermia (5-6 times), irradiation (total 30 Gy) and 5-fluorouracil suppository (2,000-2,500 mg). The subjects were 31 patients given combined treatments and 28 patients given surgery alone. The results were as follows: 1. Histologically, therapeutic effects were recognized in 80.6% of patients receiving combined treatments. 2. The mean distance from the adventitia to the site of cancer infiltration was 6.54 mm in the combined treatments group and 3.35 mm in the surgery alone group. The difference between the two was significant (p < 0.05). 3. The rate of local recurrence in the combined treatments group was less than that in the surgery alone group. 4. No systemic side effects nor severe complications were observed during hospitalization in the combined treatments group. 5. The survival rate of the combined treatments group was higher than that of the surgery alone group. It was considered that combined preoperative treatments for rectal cancer were beneficial to survival and local control.