Twenty-eight patients who had received radical treatment with X rays to tumors of the head and neck presented with advanced recurrent tumors, 23 of them had also undergone surgery and 10 had more than one operation. Seven had also received chemotherapy. They were treated with neutrons to a tumor dose of 1560 cGy in 12 fractions over 26 days using the techniques of the Hammersmith Unit. Twenty-three of the tumors (82%) underwent complete regression that was maintained in 15 for at least 12 months. Despite the damage done by the previous radiation and surgery to the normal tissues, 15 patients had no complications following neutron therapy. In six patients, there was major necrosis, in seven others, this was minor. Eight tumors recurred. Five patients responded with partial regression of their tumors. The median survival was 20 months (range 4-69 months).