Orbital complications of rhinosinusitis can be life-threatening. Accurate diagnosis by computerized tomography (CT) scanning, immediate administration of intravenous antibiotics and surgical drainage are the recommended management strategy. Faulty diagnosis by CT scan may lead to visual deterioration, intracranial complications and even fatality. The purpose of this study is to increase the awareness of the possibility of misdiagnosing orbital abscess (OA) as subperiosteal orbital abscess (SPOA) and propose a novel surgical technique to overcome this surgical circumstance.Three cases of OA and 29 of SPOA cases that were surgically managed between 1998 and 2008 were retrospectively reviewed.Three cases of OA diagnosed by CT scan as SPOA were primarily medically treated by intravenous antibiotics. Once the therapeutic management failed to resolve the condition, endonasal endoscopic surgery (EES) was carried out, upon which the diagnosis of OA was made and drainage successfully achieved.Whenever SPOA is diagnosed by CT scan and no purulent discharge is evidenced after removal of the lamina papyracea, OA should be suspected and incisions along the orbital periosteum should be made to release the pus from the orbit. The EES approach in cases of OS and SPOA can confirm an accurate diagnosis.