Very little is known about the pathogenesis of tuberous sclerosis. Over the past 10 years, however, increasing numbers of reports on adenomatous diseases in association with tuberous sclerosis have been published. A case of hypercalcaemia and parathyroid adenoma in association with tuberous sclerosis is presented, of which there has been one such report published previously. This association might be another manifestation of this complex disease: it is therefore recommended that plasma calcium concentrations should be measured in such patients.