Introduction: Maxillary sinus hypoplasia consist in maxillary sinus volume decrease, due to its walls retraction, causing eye displacement, manifested as enophthalmia, and still its real prevalence is unknown. In most of cases, it is unilateral and attack patients between third and fifth life decades, without differences between sexes. The diagnostic is confirmed by face computed tomography, which shows maxillary sinus opacification with eye floor retraction. Other founds are maxillary infundibulum occlusion, uncinate process lateral retraction, and middle turbinate lateralization.