We present a 16-year-old male patient with Marfan's syndrome who presented with quadriparesis from a Type I Chiari malformation (CM) with basilar invagination and a syrinx. The condition resolved after transoral odontoidectomy and occipitocervical fusion without posterior decompression of the CM. Thus, ventral decompression alone can resolve a cervical syrinx in patients with compression of the foramen magnum.