This case report describes a successful implant-prosthetic rehabilitation of an atrophic posterior mandible with 4-mm-long implants. The patient refused to undergo any reconstructive surgery, and because the available bone up to the inferior alveolar nerve was only 5 mm or less, the patient received four implants of 4-mm length. Four months after implant placement, a provisional prosthesis was put in place; after another 4 months, this was then in turn replaced with a definitive prosthesis. The use of such short implants allows a fixed prosthetic solution without the need for vertically augmenting the mandibular bone. This procedure considerably reduces intra- and postoperative patient discomfort compared with reconstructive surgery for the placement of longer implants. The follow-up time was 1 year after implant loading.