One hundred fifty-nine partially edentulous patients, ranging in age from 17 to 70 years, were treated with the Brånemark implant system at nine centers throughout the world. The patients were followed for 5 years in a prospective study focusing on implant success and prosthesis stability. Plaque and gingival indexes, as well as probing depths, were recorded around teeth and implants. The marginal bone level at implants was determined from intraoral radiographs. The stomatognathic function and possible complications were also reported. Initially, 558 implants were placed in 68 maxillae and 91 mandibles of Applegate-Kennedy classes I, II, and IV. Of the placed implants, 528 were reexposed at the abutment operation, whereafter 521 were loaded with 197 freestanding fixed prosthetic restorations in a total of 154 patients. During the follow-up period, a total of 27 patients dropped out or were excluded because of nonconformity with the protocol. This meant that 116 implants (80 withdrawn [14%] and 36 failed [6%], and 32 fixed prostheses [16%]) were not reexamined at the final follow-up visit. Based on the remaining implants, the cumulative implant success rates were 92% and 94% for maxillae and mandibles, respectively, and the corresponding prosthesis stability was 94%. Plaque and gingivitis indexes showed a similar pattern of good health around both natural teeth and titanium abutments. The marginal bone loss during the 5-year period did not exceed 1 mm as a mean for all implants analyzed. During the follow-up period, few complications were reported, the most frequent being resin fractures and loose gold screws. The outcome of the study indicated that safe and predictable treatment results can be obtained for 5 years in partially edentulous jaws treated with the Brånemark implant technique. Keywords: Brånemark system, oral, osseointegration, partial edentulism, titanium implants