Patella is a very uncommon site for primary bone tumours and fibrous dysplasia lesion in patella has never been reported. Fibrous dysplasia is a benign fibrosseous lesion of the bone where the fibrous connective tissue replaces the normal bone.We report a case of 23 years female with 7 years history of progressive swelling and anterior knee pain. Radiographs showed enlarged, deformed patella like a shape of banana. The patient underwent patellectomy with extensor mechanism repair and biopsy proved to be fibrous dysplasia.Fibrous dysplasia involving patella is very rare and never been reported earlier. Although primary patellar neoplasm are not common but should be kept in mind in chronic anterior knee pain with swelling for early diagnosis and intervention with intralesional therapy otherwise patellectomy has to be done in more advanced, deformed and enlarged lesions.