BACKGROUND: Xenografts can be produced in various particle sizes by using different bone types. Currently, there is no consensus about the ideal type of xenograft for sinus augmentations, and this choice depends on the personal ex-perience of clinicians. This retrospective study aimed to evaluate the effects of three different xenografts used in sinus augmentation simultaneously with implant placement on the survival of the implants and the dimensional changes of the region. METHODS: One hundred nine sinus augmentations and 164 implants were evaluated in 76 patients. Three different xe-nografts were used: 41 Gen-Os (R) (250-1000 mu m, Corticocancellous; Tecnoss, Giaveno, Turin, Italy), 35 Bio-Oss (R) (1000-2000 mu m, Cancellous; Geistlich Biomaterials italia S.r.l., Vicenza, Italy) and 33 Apatos-Cortical (R) (600-1000 mu m, Cortical; Tecnoss). The preoperative, postoperative, and follow-up (21 +/- 8.8 month) radiographs were evaluated for the dimensional changes and the implant survivals. The data were statistically analyzed. RESULTS: Among the implant failures; 3 (5.6%) in 53 implants in Apatos, 2 (3.6%) in 55 implants in Bio-Oss, 9 (16%) in 56 implants in Gen-Os, and 14 (8.5%) total implant failures were observed. This difference between the groups was statistically significant and was due to the high loss rate in the Gen-Os (P=0.044). There was a mean difference of-1.8 +/- 1.5mm between the measured bone heights on postoperative day (14.2 +/- 2.4mm) and the last follow-up (12.4 +/- 2.5 mm). While the loss of height was not affected due to the graft type (P=0.981), the general 12.6% vertical loss was statis-tically significant (P<0.0001), also the length of implants placed reduced this loss (P=0.036). CONCLUSIONS: Within the limits of this retrospective study, it can be concluded that: 1) The sinus augmentation pro-cedures with thicker particle size grafts achieved higher success rate; and 2) over the time, 12.6% loss may occur in the height of grafted area.