Most of axillary nerve injury develops after dislocation of glenohumeral joint, proximal humeral fracture and direct blow to the deltoid muscle. Some cases in volleyball players and athletes playing contact sports like hockey, football have been reported. But axillary nerve injury after swimming with butterfly stroke has not been reported previously. We experienced a 34 year old female who had weakness in abduction and sensory impairment in lateral aspect of right arm after butterfly stroke. She was transferred from local clinic to our Rehabilitation Department because symp-toms were not improved despite conservative treatment. We diagnosed her as axillary nerve injury by typical clinical manifestations and electrodiagnostic study. Additionally, we detected type II superior laburum anterior posterior lesion combined with axillary nerve injury in shoulder magnetic resonance image. We should consider possibility of axillary nerve injury in a patient with shoulder pain and weakness after swimming like butterfly stroke. (J Korean Acad Rehab Med 2005; 29: 541-544)
