Patients with hemophilia are living longer as a result of improved therapeutic measures. Associated with this longevity is the increased occurrence of complications affecting the osseous system. One of the more serious bone complications is the hemophilic pseudotumor or hemophilic cyst. We studied its diagnosis, treatment, and complications, and report a case of an early hemophilic cyst occurring in a new location, the proximal part of the left clavicle. The increased incidence of this complication should alert the clinician to the possibility of these lesions appearing in previously unreported sites and demonstrating atypical roentgenographic features. Early recognition and treatment is essential if optimal therapeutic results are to be obtained.