Osteoporosis is a multifactorial progressive skeletal disorder characterized by compromised bone mass which predisposes to increased fracture risk. Fractures are often associated with increased morbidity, mortality, loss of function, deformity and functional limitations. The major public health impact of osteoporosis calls for organized strategies for both primary and secondary prevention. Even if pharmacological therapeutic interventions provide substantial reduction in fracture risk, prevention of osteoporosis should begin early in life. Primary prevention during growth and adolescence aims to obtain a high peak bone mass, adequate calcium intake, exercise and early diagnosis and treatment of potential skeletal deformities. Secondary prevention, during middle age, aims to identify the subjects with low bone mass and more than one risk factor for an osteoporotic fracture, in order to plan multifactorial interventions with a special emphasis on nutritional aspects and individualized sport therapy.