The occurrence of an osteochondroma in the carpus is very rare and its excision is indicated in the case of significant symptoms or change in its appearance. The diagnosis is often made in adulthood due to the onset of a functional problem even though development of the tumour occurs during skeletal growth. We report the case of a 38 year old patient, with no antecedent trauma, who presents with simultaneous exostoses on the dorsal and palmar surfaces of the capitate, which has not been previously described in the literature. The existence of a bipolar lesion extending anteriorly and posteriorly in the carpus is a possibility which may not be apparent and renders plain radiograph insufficient in the investigation of such a lesion. CT scan and MRI scan are indispensable in the investigation of this kind of carpal lesions, allowing better visualization of the base of the tumour, the expansion of the tumour and relation to the neighbouring soft tissues and the presence of malignant degeneration.