Postoperative maxillary cysts (POMCs) are considered as a delayed complication, which occurs after several years of occurring many years after maxillary sinus surgery. The variable symptoms related to POMCs include swelling and pain in the buccal region, discomfort in the maxilla or maxillary teeth, and exophthalmos. Symptoms related to the teeth may be confused with those of an odontogenic disease. Herein, We report about the delayed diagnosis of bilateral POMCs in the maxillary region 30 years after Caldwell-Luc surgery for maxillary sinusitis.