Objectives: The study aimed to identify the patients with pathological lesions in the maxillary sinuses in which the reported symptoms might be indicative of odontogenic origin, as well as to establish specific causative risk factors promoting their development. Methods and Materials: The study covered 44 patients with suspected odontogenic maxillary sinusitis. Dental examination and Cone Beam Computed Tomography were completed. The age of patients ranged between 19 and 69 years, and the mean age was 43 (SD = 13.9) years. Results: Out of 44 patients, 22 (50%) had non-odontogenic lesions in maxillary sinuses, while in 15 (34.1%) dental origin was established. In the remaining 7 (15.9%) patients, no pathological changes were found in the sinuses. The median of reported symptoms was 10 months (Q1 = 4, Q3 = 24). The reported complaints were not associated with the actual cause of pathological lesions. Conclusions: Odontogenic cause of the lesions in the sinuses should primarily be hypothesized, especially in patients with long-term disease symptoms, also regarding any unilateral inflammations.