STUDY DESIGN: A case report on cervical instability detected in a patient with Sotos syndrome, along with a review of the literature on Sotos syndrome and associated spinal findings. OBJECTIVE: To present the case of a patient with a C3-C4 anterolisthesis occurring in the setting of Sotos syndrome and explore a possible association between the two. SUMMARY OF BACKGROUND DATA: Sotos syndrome, a rare overgrowth syndrome with slightly more than 300 cases reported in the English literature to date, is characterized by a unique constellation of symptoms and signs including musculoskeletal findings such as scoliosis, pes planus, generalized ligamentous laxity, and increased growth rates. Cervical instability as part of this syndrome is unreported and rarely presents as a C3-C4 anterolisthesis. METHODS: A case report detailing the evaluation and treatment of a cervical instability in a 3-year-old with Sotos syndrome. RESULTS: A previously unreported cervical spine instability in Sotos syndrome is described. The patient underwent a posterior spinal fusion of C3 and C4 to avoid complications from the instability. The surgery achieved good results. CONCLUSION: We outline a possible connection between Sotos syndrome and cervical instability, which may be associated with the unique features of this syndrome including ligamentous laxity or macrosomia and/or with unrecognized injury. Awareness of this occurrence is important for enhancing early detection and correction of this condition.