Introduction: Occipital condyles and articular processes of atlas vertebrae form the atlanto-occipital joint. This joint contributes to flexion and extension of head and neck. Hypoplasia of the occipital condyle (HCO) is an unusual developmental anomaly, being shown isolated or as a part of a syndrome. While diagnosis and clinical management of HCO corresponds to the medical area, some cases of HCO may be adverted by a dentist. Case: Female patient, 23 years old, asymptomatic, come to be undergone to a lateral cephalometric radiograph prior to an orthodontic treatment. In this image the posterior arch of the atlas was observed as not superimposed. In the radiographic report the presumptive diagnosis included HCO. This radiographic examination was complemen-ted with a cone-beam computed tomography examination (CBCT), which confirmed the diagnosis of HCO. Conclusion: HCO can be seen on a lateral cephalometric radiograph, and the diagnosis can be performed by a maxillofacial radiologist. Confirmation of diagnosis should be done with CBCT images to analyze bone structures, and with magnetic resonance imaging to analyze surrounding soft tissues.