Objective: To present the rare case of a displaced odontoid fracture after manipulative treatment. Clinical features: A 37-year-old, 15-week pregnant patient was referred with acute neck pain and a diffuse paravertebral swelling that started after cervical manipulation performed by her general medical practitioner 5 days before. Because of pregnancy, a cervical spine radiographic series was not obtained before treatment. Magnetic resonance imaging revealed a displaced odontoid fracture associated with a pathological process in the vertebral body of C2 and a paravertebral hematoma on the left side from C2 to C4. Intervention and outcome: After initial halo vest immobilization, an anterior-posterior fusion of C1-C2 was performed. The histological analysis showed features of an aneurysmal bone cyst. The patient was discharged and had an undisturbed pregnancy and was without any neurological complications. Conclusions: Because of the weakening lesion in C2, the spinal manipulation most likely caused the displaced odontoid fracture. Special imaging should be performed, preferably with magnetic resonance imaging, when a patient experiences significant new symptoms after cervical manipulation.