The intrauterine device is the most widely used reversible method of contraception in the world today, particularly in developing countries where it is used by 14.5% of women of reproductive age. In the developed world, this percentage is only 7.6%. There are marked regional differences with the highest use in Eastern Asia and the lowest in North America. Such differences between regions and countries can be explained by a number of factors at the individual, service delivery, program and policy levels. The situation in seven countries is briefly described to illustrate this and to conclude that this method of contraception is largely underutilized in many parts of the world, where it could play a significant role in improving women's health.