Implant treatment is nowadays requested as an alternative mode of treatment for both total and partial edentulousness. The purpose of the study was to assess the maximum number of possible implant sites in a group of adults. The study material comprised 579 persons divided into the age-groups 20, 30, 40, 50, 60 and 70 years. Based on radiological examination, the subjects were grouped according to Eichner's index. They comprised both dentate and edentulous individuals. Templates, marked with cylinder implants of different dimensions, were placed over edentulous regions. The possible number of cylinder-shaped endosseous implants that could be placed anterior to the second molar was assessed in relation to bone availability and anatomical structures. Gaps treated with fixed bridges were not registered. Altogether 1,048 presumptive fixture sites were marked, of which 78% in the age-groups 60 and 70 years. Eichner groups C 1-3, which comprised the edentulous persons, constituted 12% of the subjects and accounted for 57% of the possible number of implants. All edentulous mandibles and 70% of the edentulous maxillae were judged suitable for placement of implants. On average 5.5 and 5.8 sites were marked per edentulous maxilla and mandible, respectively. Groups B1-4 comprised 21% of the subjects and accounted for 37% of the implants. It is discussed that implant treatment in totally edentulous jaws will increase in relative terms in Sweden as in other Scandinavian countries, i.e. the percentage of edentulous jaws treated with implants will increase. In absolute terms, however, the treatment will probably decrease owing to a marked decrease in the number of edentulous individuals. The future need for implant treatment in the residual dentition will probably increase but it is difficult to predict by how much.