Two groups of elderly edentulous patients with implant-supported mandibular overdentures were compared. There were 25 patients with an average age of 62.2 years and 34 patients with an average age of 68.9 years treated in Toronto and in Bern, respectively. A high incidence of compromised general health was found in both groups. All patients had been treated in the years 1984 through early 1987 and had worn their implant-supported overdentures for the previous 5 years. Regular monitoring of the patients was done by two investigators using periodontal and radiographic parameters. Two different implant systems were used: Brånemark fixtures in Toronto and ITI implants in Bern. Most overdentures were retained by only two implants in both groups. The 5-year longitudinal data show a similar high success rate (> 90%) for both patient groups.