Recent advances in the understanding of the epidemiology of osteoporosis suggest that certain parts of the current European guidelines for the registration of drugs in osteoporosis might be no longer substantiated. The object of this review is to provide the European regulatory authorities with an evidence-based working document providing suggestions for the revision of the "Note for guidance for the approval of drugs to be used in postmenopausal osteoporosis" (CPMP/EWP/552/95). Following an extensive review of the literature (1990-2004), the Group for the Respect of Ethics and Excellence in Science (GREES) organized a workshop including European regulators, academic scientists and representatives of the pharmaceutical industry. The outcomes of this meeting reflect the personal views of those who attended and should not, in any case, be seen as an official position paper of any regulatory agency. The group identified a certain number of points that deserve discussion. They mainly relate to the nature of the indication being granted to new chemical entities (treatment of osteoporosis in women at high risk of fracture instead of prevention and treatment of osteoporosis), the requirements of showing an anti-fracture efficacy on all or on major nonvertebral fractures (instead of the hip), the duration of pivotal trials (2 years instead of 3) and the possibility of considering bridging studies for new routes of administration, new doses or new regimens of previously approved drugs. The group also recommends that an indication could be granted for the treatment of osteoporosis in males on the basis of a placebo-controlled study, with bone mineral density changes after 1 year as the primary endpoint, for medications approved in the treatment of osteoporosis in women at high risk of fractures.