Purpose: The objective of this study was to assess the efficacy and safety of a minimally invasive sinus lift using an inflatable water balloon followed by bone grafting and implant placement. Materials and Methods: A total of 28 patients with a single tooth missing in the posterior maxilla underwent a water balloon sinus lift, followed by bone grafting and implant placement. Baseline bone height was 4.92 ± 1.24 mm. Implant site preparation employed a pilot drill and osteotomy followed by water balloon elevation. The mean inflated balloon volume was 0.67 ± 0.17 mL. Bio-Oss was filled under the elevated sinus membrane using a dedicated instrument. Twenty-eight total implants (diameter: 3.8 to 5.0 mm) were placed. Pre- and postoperative panoramic films or computed tomographs (optional) were taken for every case to measure and compare the results of the sinus membrane lift using a water balloon. Postoperative patient reactions including swelling, discoloration, discomfort, hematomas, and disability were recorded. Results: Successful sinus membrane water balloon lifting procedures were performed in 26 cases; two procedures were aborted due to sinus membrane perforation. A total of 26 implants were placed. The mean inflated balloon volume was 0.67 ± 0.17 mL and radiographic examination showed the mean elevated height by balloon to be 10.9 ± 2.06 mm. Computed tomography showed the bone graft distributing evenly around implants. Patients were extremely pleased with the results and needed very little medical attention after surgery. The mean follow-up was 15.9 ± 2.94 months. One implant was lost due to infection. Conclusion: The use of a water balloon to elevate the sinus membrane is a truly minimally invasive technique and is associated with very little discomfort. This method has encouraging results, is easy to learn, and is associated with low complication rates.