Displaced fracture of the acromion without associated shoulder injury occurs rarely. A 31-year-old gentleman presented with an isolated acromion fracture resulting from a direct trauma to the top of his left shoulder. Open reduction and internal fixation using multiple pins was performed and the fracture was closed without complications. The patient achieved excellent shoulder function and ranked as satisfied in the constant shoulder score almost 14 months following the surgery. Fixation with pins can provide adequate stability in this rare type of shoulder fracture.