BACKGROUND : This case report discusses a modified approach for maxillary sinus augmentation, in which platelet-rich fibrin, endoscope, simultaneous implant placement, and sinus floor elevation (PESS) were applied for a maxillary sinus floor lift in a 40-year-old patient. METHODS : A 40-year-old woman suffered missing upper right first molar. Implant stability quotient and cone-beam computed tomography (CBCT) were used to evaluate the diagnosis. CBCT showed insufficient posterior maxillary bone with a mean residual alveolar bone height of only 3.5 mm. The patient underwent a minimally invasive sinus floor elevation endoscopically. The sinus membrane was elevated in two stages, and a 12-mm implant was placed immediately. At 3 mo postoperatively, the final impressions were accomplished, and a full-ceramic crown was fit-placed. A 6-mo follow-up demonstrated satisfactory aesthetic and functional results. CONCLUSIONS : This is the first report to use an endoscope for maxillary sinus floor lifting in cases with severe and insufficient bone height. This case report demonstrates the advantages of the PESS technique, which include minimal invasiveness with high precision, being applicable in cases with a residual alveolar bone height < 4 mm with a promising result, and a shortened treatment period from 12 to 3 mo.