Objective: To determine dental agenesis prevalence in Sayada, Tunisia, a town from where many patients attend the Pediatric Department of Monastir University Dental School for such abnormalities, and to analyze its mode of inheritance. Method and Materials: A total of 262 schoolchildren in permanent dentition (134 females and 128 males) aged 12 to 18 years (mean, 14.1 ± 1.2 years) were examined to detect dental agenesis. In the case of a missing permanent tooth, a panoramic radiograph was taken to confirm diagnosis. A family survey questionnaire was completed for each case of multiple agenesis (at least 4 teeth missing). Results: Findings revealed a dental agenesis prevalence of 13.3%. Altogether, 62 teeth were missing. No case of syndromal agenesis was detected; however, 12 children presented multiple agenesis (34.3%). The family survey was completed for only 9 of these subjects. Conclusion: Literature review showed a lower dental agenesis prevalence (3% to 7%) than did the present study. In the present study, females were more affected by this abnormality than males (16.4% and 10.3%, respectively). With the exception of third molars, the tooth most often missing was the mandibular second premolar (30.6%), followed by the maxillary second premolar (17.7%); hypodontia seemed to be symmetrical. Family surveys revealed a high rate of consanguinity in Sayada. Pedigree analysis of 9 families showed that dental agenesis was probably related to an autosomal dominant inheritance. Keywords: dental agenesis, epidemiology, mode of transmission, pediatric dentistry, pedigree, Tunisia