Post-traumatic syringomyelia is now a well known entity and occurs months or years after a spinal cord injury. The presenting symptoms are usually pain, progressive motor weakness, sensory changes, and increased spasticity. Profuse sweating or hyperhidrosis can be a symptom of the post-traumatic syrinx or can occur in autonomic dysreflexia provoked by peripheral stimuli. We present two patients with cervical spine fractures whose presenting symptom of post-traumatic syringomyelia was hyperhidrosis affected by posture. The pathophysiology involved and the management of these patients is discussed.