OBJECTIVE The objective of this study was to estimate the incidence of non-syndromic supernumerary premolars, to classify them and to identify the complications related to them. METHODS This retrospective cohort study was composed of 8400 panoramic radiographs of patients who presented at our Oral and Maxillofacial Surgery Services from January 1998 to May 2008. The number of supernumerary premolars, their localization, the ages and the sex of the patients, any associated complications and treatment methods were estimated. CONCLUSIONS A total of 20 supernumerary premolar teeth were found in 10 of the 8400 patients (0.24%) with 7 of those being females and three males. Three patients had pain localized to the mental foramen and one patient had resorption in the root of the adjacent tooth. In these series, 18 supernumerary premolar teeth were extracted. In contrast with previous studies, this study suggested that this phenomenon is more frequently encountered in females than in males. The presence of complications associated with the supernumerary premolars in 4 patients necessitated consideration of surgical intervention as a treatment choice for these teeth. Otherwise, they should be kept under observation.