Following radical oral cancer surgery and postoperative adjuvant radiotherapy with a total dose of 60 Gy, 71 IMZ and 1 50 Branemark implants were placed in the mandibles and 28 Branemark implants were placed in the maxillas of 60 patients between 1985 and 1995. Adjunctive hyperbaric oxygen therapy was not used. Osteoradionecrosis of the mandible occurred in two patients (3.4%), and necrosis of soft tissue in the floor of the mouth region occurred in three patients (5.2%). Twenty-one implants (18 in the mandible and 2 in the maxilla) were not osseointegrated when surgically exposed. In subsequent follow-up, 17 mandibular implants and 5 maxilary implants lost their osseointegration. The life table method indicated that 5-year actuarial implant success rates in the irradiated mandible were 77.5% for the IMZ system and 83.5% for the Branemark system. These differences were not statistically significant. Retrospective analysis indicated that the success of implants in the irradiated mandible is determined after an interval of 18 to 24 months. For a small number of Branemark implants in the irradiated maxilla, an actuarial success rate of 85.5% was found.