Ten patients (3 maxilla, 7 mandible), who had been treated for a head and neck malignancy by undergoing radiotherapy, had 42 implants (10 maxillary, 32 mandibular) placed into the irradiated sites and either an overdenture or a fixed prosthesis fabricated. Of the 10 implants placed in the maxilla, 6 were lost; however, there was a 100% survival rate of the implants placed in the m andible (mean duration = 33 months). The use of longer implants and pre- or postimplant hyperbaric oxygen may be necessary in maxillary situations.