Endodontic implications of the maxillary sinus comprise extension of periapical lesion into the sinus. Though the actual cause of sinusitis is difficult to determine accurately, majority ofthe cases occur through a dental cause. The purpose ofthis paper was to present the management of maxillary sinusitis of endodontic origin. A 48-year-old generally healthy male patient reported to the dental clinic for the implant placement in the area of missing# 26. During the procedure, the dental surgeon noticed a thick granulation tissue in the deep area with a painful sensation. Further, endodontic consultation revealed the tooth# 25 was endodontically treated 9 years ago, and cone beam computed tomography showed periapical lesion perforated the maxillary sinus. Extraction and enucleation were done and the biopsy sent to the histopathological laboratory revealed periapical granuloma. After 2 months, patient was asymptomatic and ENT examination showed the floor of maxillary sinus with reduced hyperplasia. Symptoms of maxillary sinusitis can induce pain of dental origin, and a cautious differential diagnosis is essential when dealing with pain in the maxillary posterior region.