We describe four children with idiopathic juvenile osteoporosis. All patients were initially seen between the ages of 10 and 13 years and spontaneously recovered following puberty. We review 27 similar cases reported in the literature. Theories on the cause of idiopathic osteoporosis in children are critically discussed. It may be that milder forms remain undiagnosed because of the self-limited course and the pain being confused with a variety of rheumatic disorders. It would be worth observing these cases to determine if they are otherwise prone to development of osteoporosis during pregnancy or in later life.