A 54-year-old man visited our hospital with complaints of severe pain in the neck and the right upper limb. His MR (magnetic resonance) imaging showed a cervical syringomyelia associated with Chiari I malformation. After one month, his complaints vanished smoothly, and the repeated MR imaging revealed shrinkage of the syrinx. The mechanisms of spontaneous resolution of syringomyelia were discussed according to some relevant literature.