Aim of the study: to asses the relationship between Maxillary Sinus Floor and Maxillary Posterior Teeth Root Tips Using Dental Cone-beam Computed Tomography and digital panoramic radiography. Materials and methods: the relation between upper first and second premolars and first and second molars root tips (154 roots) and the maxillary sinus floor was assesed using both digital panoramic radiography and cone beam computed tomography by drawing vertical and horizontal lines form root tips to maxillary sinus floor using built in measurement tools. Results: The palatal root of second molar showed the closest vertical and horizontal relationship to the maxillary sinus floor while buccal root of first premolar showed the farthest vertical relation to the maxillary sinus floor in Egyptian patients.