The role of calcium and vitamin D supplementation in the treatment of osteoporosis has been extensively studied. The aim of this paper was to reach, where possible, consensus views on five key questions relating to calcium and vitamin D supplementation in the management of osteoporosis. Whereas global strategies that target supplementation to the general population could not be justified in terms of efficacy and health economics, there is a clearer rationale for supplementing patients who are at increased risk of osteoporosis and those who have developed osteoporosis, including those already taking other treatments for osteoporosis. The combination of vitamin D with calcium may be beneficial in terms of efficacy and, perhaps, for optimising adherence.