The purpose of the present study, which used anorganic bovine bone (Bio-Oss) with and without autogenous bone as the augmentation material, was to compare the results of sinus elevation performed without a membrane (control) with the results of sinus elevation performed with either a short-term bioabsorbable membrane (Bio-Gide) or a nonabsorbable membrane (Gore-Tex) with regard to both vital bone formation and implant survival. Sinus lifts were performed on 51 patients (38 unilateral, 13 bilateral) with the delayed placement of 135 implants. Histomorphometric data were obtained at the time of implant placement, 6 to 10 months following the grafting procedure. Vital bone formation was 17.6%, 16.9%, and 12.1%, respectively, for the Bio-Gide, Gore-Tex, and no membrane groups. Of the 135 implants placed there were 3 failures (2 Bio-Gide, 1 Gore- Tex). There was no significant difference between the membrane groups as to vital bone formation and implant survival.