The anterior inferior iliac spine (AIIS) is a newly recognized etiology of extra-articular hip impingement. The purpose of this article is to describe an arthroscopic technique for AIIS decompression causing extra-articular hip impingement. Arthroscopic decompression of subspine impingement is a novel procedure that can be used to successfully relieve hip pain and improve hip function and range of motion cause by AIIS impingement.