Abstract: Objective: To evaluate the clinical outcome and radiographic new bone formation of simultaneous lateral sinus lift without grafts. Methods: Twenty posterior partially edentulous patients with residual bone height (RBH) between 4-5mm were chosen to receive the lateral sinus lift. Patients were randomly assigned into two groups. Trial group: 10 patients received 12 implants using lateral sinus lift technique without grafts. Control group: 10 patients received 11 implants using lateral sinus lift technique with hydroxyapatite graft. All patients were followed regularly after the surgery up to 12 months. The success rate of the implants, the radio examination of the bone height and implant stability quotient (ISQ) were checked during the revisits.Results: All implants were stable during the study period. In the trial group, the mean values of the mesial aspect increased from (4.50±0.21) mm to 6.88±0.85 mm at 3 months and to (7.42±0.66) mm at 6 months, stayed stable at (7.55±0.55) mm when reached 12 months. The same pattern was observed in the distal side. In the control group, RBH of the mesial aspect decreased from (11.29±0.64) mm to (10.11±0.62) mm at 3 months and to (9.51±0.39) mm at 6 months, stayed stable at 9.59±0.39 mm when reached 12 months. The similar changing pattern was discovered in the distal aspect. The differences between two groups were significant (P<0.05). The ISQ value increased from (53.92±7.31) to (64.77±9.22) at 6 months in the trial group and from (56.23±8.05) to (67.29±8.34) in the control group (P<0.05). Conclusion: The short-term clinical result of lateral sinus lift without grafts was satisfied and some extent of endo-sinus bone gain could be observed.