The diagnosis of osteoporosis is based on low bone mineral density (BMD) and/or the occurrence of fragility fractures. The majority of patients, however, have also abnormally low bone matrix mineralization. The latter is indicative of alterations in bone turnover rates and/or in kinetics of mineral accumulation within the newly formed bone matrix. Osteoporosis therapies can alter the bone matrix mineralization according to their action on bone turnover and/or mineralization kinetics. Antiresorptives, including the most widely used bisphosphonates, reduce the bone turnover rate resulting in a decrease in heterogeneity and an increase in the degree of mineralization toward to or even beyond normal values. Anabolic agents increase the bone volume and the amount of newly formed bone resulting in a likely transient decrease in mean degree and homogeneity of mineralization. Hence, the measurement of bone matrix mineralization is a sensitive tool to evaluate the response to therapy.