The literature concerning tumours of the patella is briefly reviewed. 2. A case of primary osteoma of the patella is reported. 3. Though a malignant tumour was excluded by roentgenology, age of the patient and localisation, a firm diagnosis could not be made before excision and histological examination of the enucleated tumour. 4. Some considerations concerning the origin of osteomas from the pathological point of view have been made.