The aim of this study was to identify the risk factors associated with sinus membrane perforation and the effect of sinus membrane perforation and other risk factors on graft success and postoperative sinusitis. Sinus membrane perforation, graft failure, and postoperative sinusitis were tested for an association with age, sex, operator experience, side of the operation, residual bone height, presence of septa, presence of a mucous retention cyst, and smoking (chi(2) test). Logistic regression analysis was used to model the odds ratio (OR) with corresponding risk factors. One hundred and twenty patients were included in this study. A total of 22 (18.3%) perforations occurred. A residual bone height of 3-6 mm (OR 6.808, P = 0.002) and presence of septa (OR 4.023, P = 0.025) were identified as significant risk factors. Twenty-eight (23.3%) sinus grafts were classified as failed. Membrane perforation (OR 16.819, P < 0.005) and residual bone height of 3-6 mm (OR 5.363, P = 0.01) were identified as significant risk factors for graft failure. None of the risk factors investigated in this study was significantly associated with postoperative sinusitis. These results suggest that the presence of septa and a residual bone height of 36 mm are associated with an increased risk of sinus membrane perforation, and that sinus membrane perforation has a negative effect on graft success.