The purpose of this paper is to review the normal physiologic processes of skeletal accretion, abnormalities that may occur in children with chronic illnesses, and therapeutic maneuvers that the clinician may be able to employ to prevent or partially correct abnormalities of skeletal growth. Skeletal maturation in children is dependent upon bone formation exceeding resorption, whereas in adults these two fundamental processes of homeostasis are closely balanced. Skeletal growth is effectively completed at the end of the period of adolescent growth acceleration with closure of the epiphyses. An important determinant of future fracture risk and osteoporosis is the peak bone mass achieved during this second decade of life. If the hereditarily determined peak bone mass is not established during that time, the patient will enter young adulthood with osteopenia, an increased fracture risk, and accelerated postmenopausal osteoporosis or involutional osteoporosis. Thus osteopenia and osteoporosis have their origins in childhood and adolescence.