A case of aneurysmal bone cyst of the patella in a 15-year-old woman was presented. An ABC occurring in a female patient is rare, and to our knowledge this is the first report in the literature. All other reports of patellar ABCs reported have occurred in young black men [2, 3]. The radiographic findings and clinical presentation were stressed since they are typical of all benign patellar tumors. Although radiographic findings are usually typical of patellar tumors, CT and MRI may be used for staging and standardization of operative treatment. MRI is also helpful for examining the integrity of the patellar tendon and quadriceps since many of these patients present with malfunction of the extensor mechanism [14].