Ten patients with advanced, unresectable carcinoma of the pancreas were treated with intratumoral high-dose injections of OK-432 and their therapeutic responses assessed from the clinical standpoint in the past four years since 1977. Following the treatment, 7 (78%) of 9 patients evaluated by the Karnofsky criteria fell under Category I, of whom 2 were classified under I-C. Five patients (50 %) showed performance status scores of≧80 (on the Karnofsky scale) following operation. A substantial to complete relief of pain was achieved in 3 (60 %) of 5 patients who had complained of pain prior to surgery. The average survival period in the group of OK-432-treated patients did not differ significantly from that in a control group. However, a patient in the treated group is still living 13 months after operation. The results indicate that intratumoral high-dose OK-432 therapy is notably effective for prolongation of survival and for relief of pain with rarity and mildness of side effects.