We experienced a patient who presented recurrent episode of pain, swelling, and weakness of right lower leg. She was diagnosed as Behcet's disease 1 year ago. The symptom was developed after exercise and was relieved by rest. After several different examinations and differential diagnoses, we confirmed the diagnosis as chronic exertional compartment syndrome on the basis of measuring intramuscular compartmental pressure. The patient was recommended to take a rest and she got a shoe-modification, prescription of ankle- foot orthosis, and physical therapy. She experienced symptom relief after that. Chronic exertional compartment syndrome is uncommon disease caused by reversible ischemia secondary to increased pressure within a closed osseofascial compartment after exercise producing expansion of muscle volume. (J Korean Acad Rehab Med 2006; 30: 191-194)