INTRODUCTION: Prosthetic rehabilitation with implants in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, rigid anchorage can also be achieved using long zygomatic implants. The aim of this study was to evaluate the surgical outcomes of rehabilitation of atrophic posterior maxillary ridges with zygomatic implants using the zygomatic success code (ZSC) and derive the success grade for the procedure based on the observed results. MATERIALS AND METHODS: A total of eight implants were placed in an extrasinus technique based on the zygomatic anatomy-guided approach. The following were evaluated postoperatively - primary stability, maxillary sinus pathology, soft-tissue healing and prosthetic offset. The ZSC score was calculated, and success grading was given with ZSC based on Aparacio .,'s guidelines. RESULTS: One implant had Grade 1 mobility and partial maxillary sinus opacification, 25% ( = 2) revealed a mild recession exposing the implant head and 12.5% ( = 1) showed significant recession up to 7 mm. The prosthetic offset of zygomatic implants was scored -1 for all eight implants. Five implants were given a success code of 1/1/1/1 and a success grade of Grade I, two implants were given code 1/1/2/1 with Grade II and one implant 2/2/3/1 and grade III. The results imply that zygomatic implants can be a successful option in maxillary rehabilitation. DISCUSSION: The zygomatic implants, as a graft less and promising solution to the rehabilitation of atrophied maxillary arches, have excellent surgical outcomes with varied advantages.