Tooth loss adversely affects patients? health and psychosocial wellbeing. In addition, it changes mandibular morphology. Objective: To evaluate the effect of tooth loss, age, and gender on mandibular morphology. Cone-beam computed tomographic (CBCT) scans of 101 patients were examined to measure the gonial angle (GA), ramus height (RH) and condylar height (CH). Patients? age, gender, and dental status were recorded. Repeated measures analysis of variance (ANOVA) was used to assess the impact of gender, age, and tooth loss on the GA, RH and CH. The mean measurements of the GA, RH and CH were compared between dentate/edentulous patients after splitting by gender. The GA was larger in edentulous patients compared to dentate ones, in females than in males, and in older than in younger. RH on the right side was significantly longer than on the left side (P< 0.0001), and also longer in males and younger patients. CH was shorter in younger than in older patients and in dentate than in edentulous patients. Tooth loss is associated with changes in mandibular morphology and its prevention would avoid these irreversible changes.