INTRODUCTION:The alveolar ridge splitting method is a surgical technique for horizontal ridge augmentation of narrow ridges in order to insert implants for prosthetic treatment. Objective: To evaluate one stage ridge splitting technique using piezotome with immediate implant placement for treatment of maxillary anterior undercut areas. MATERIALS AND METHODS: Seven individuals with anterior maxillary undercut defect were chosen based on a set of inclusion and exclusion criteria. In the same procedure, the individuals underwent inverted U-shaped maxillary ridge splitting with a piezotome and immediate implant insertion. The assessment comprised cone beam computed tomography analysis of bone gain at the undercut defect and bone density labial to implants in each participant. RESULTS: There was a significant bone width increase at the undercut area after four months of the splitting procedure and implant placement. The bone density labial to the implant also was found to be significantly higher than the initial measurements. All cases showed normal healing, except two cases showed soft tissue inflammation which were managed conservatively. CONCLUSION: This study showed favorable outcomes of one-stage ridge splitting and implant placement in the treatment of undercut defect at the maxillary ridge. In addition, the one-stage technique is suggested to be safer and less time consuming with no need for a second surgery.