Objectives of the procedure: Gain bone volume in the maxillary sinus region. Presentation of the case (clinical procedure step by step and scientific su-sized justifying the procedure); Female patient, 61 years old, with no systemic diseases, smoking 10 cigarettes/day. Lateral osteotomy technique described by Caldwell-Luc and modified by Tatum, increases bone volume in the posterior region of the maxilla and allows the implants placement. We performed a "Newman" incision between the 2nd premolar and 2nd molar opening the flap in order to open a bone window with a piezoelectric device and to elevate the Schneider membrane. Filled up the maxillary sinus with xenograft (Osteobiol Mp3), the bone window was covered with a collagen membrane (Evolution) and sutured with simple stitches and Supramid 4/0. Immediate results, short and medium term: After 6 months the bone gain and placed the implants was observed at the CT, the patient is rehabilitated. Discussion: The lateral osteotomy is a surgical technique widely used, reliable(1) and indicated when the residual bone height does not permit the placement of standard length implants or the use of less invasive techniques. The biphasic technique is used for residual bone heights between 1-4mm or for implant without primary stability(2). Bone grafts goal is to maintain space, mechanical stability and to guide bone formation, are crucial for osteogenesis. Six months of healing are suggested (3,4). The use of membrane to cover the lateral osteotomy together with roughened surface implants, shows the best implant survival rates (98.3%)(5). Conclusions: The lateral osteotomy technique is predictable, has great results in increasing the bone volume of posterior maxilla. Keywords: Bone grafting, sinus augmentation, sinus floor augmentation, bone substitutes, bone regeneration, case reports