Due to the introduction of new therapeutic regimen aimed at increasing and maintaining bone mass, bone densitometry in children has gained interest. As in all new fields of medicine we expect the interest in bone densitometry in children to increase in the coming years. Children pose a unique problem for those involved in the field of bone densitometry, because as time progresses the measured subject changes in shape and volume. It is therefore of importance that radiologists and clinicians gain insight in the available techniques. It is also important to keep in mind that all bone densitometry techniques have been exclusively designed, developed and validated for use in an adult population. In this article we give an overview of the available techniques and discuss the specific problems that can be expected when these techniques are used in children. In the discussion section general problems regarding bone densitometry in children are presented.