Patella is a very rare localization for osteoid osteoma. Non-specific knee complaints and difficulty to distinguish nidus in direct radiographs may cause a delay in diagnosis and make the definite diagnosis troublesome. The most effective and non-invasive method in treatment of osteoma is CT guided excision of the nidus. We present a case of patellar osteoid osteoma diagnosed by MRI scans. After being marked under CT guidance, the lesion was completely excised with a skin punch. We propose that, this method is both minimal invasive and effective in the management of patellar osteoid osteoma.