Complications were recorded in consecutive patients with osseointegrated implant-supported prostheses visiting prosthodontic specialist clinics during October and November 1991. Patients at regular follow-ups and emergency visits were included. Of the 600 prostheses examined, 28% needed some prosthodontic treatment. Complications varied widely-from simple adjustment to complete remaking of the prosthesis. The most common complications observed were related to the acrylic resin part of the prostheses. The frequency was higher in maxillary than in mandibular prostheses, and in full-arch removable and fixed prostheses than in single-tooth replacements and fixed partial dentures. Implant losses were rare (0.3% of all 2,709 implants placed) and occurred in 1% of the patients examined. Keywords: dental implants, dental materials, denture, partial, fixed, denture, partial, removable, practice management, dental