This review analyzes articles published on the presence of septa in maxillary sinuses. An automated search was conducted on PubMed using different key words. This search resulted in 11 papers in which the presence of antral septa was assessed. These septa are barriers of cortical bone that arise from the floor or from the walls of the sinus and may even divide the sinus into two or more cavities. They may originate during maxillary development and tooth growth, in which case they are known as primary septa; or they may be acquired structures resulting from the pneumatization of maxillary sinus after tooth loss, in which case they are called secondary septa. Several methods have been used in their study, direct observation on dried skulls or during sinus lift procedures; and radiographic observation using panoramic radiographs or computed tomographs. Between 13 and 35.3% of maxillary sinuses have septa. They can be located in any region of the maxillary sinus and their size can vary between 2.5 and 12.7 mm in mean length. Some authors have reported a higher prevalence of septa in atrophic edentulous areas than in non-atrophic ones. If a sinus lift is conducted in the presence of maxillary sinus septa, it may be necessary to modify the design of the lateral window in order to avoid fracturing the septa.