The case of a maxillary sinus cholesterol granuloma posing as a malignant tumor is presented. The patient was referred to the authors' clinic with symptoms typical of maxillary sinusitis, but physical examination suggested the presence of neoplasm. Radiology also resulted in confusing, tumor-like pictures. Histological examination of a preoperative tissue sample identified the process as a cholesterol granuloma, which was removed by a classic Caldwell-Luc operation. The patient has been symptom free since the operation. The pathogenesis of cholesterol granuloma is described, and the problems of establishing a diagnosis without preoperative histology are discussed.