Osteoporosis and osteomalacia are systemic metabolic bone diseases characterized by an impaired composition, architecture, and quality of bone. In light of the demographic development and the recent use of sensitive tests, both diseases are increasingly diagnosed. Subjects at high risk include elderly, chronically hospitalized patients, and nursing home residents. Patients with gastrointestinal, rheumatologic and endocrine disorders are also at risk for the development of osteoporosis or osteomalacia. In this review, we will discuss practical aspects of the clinical presentation and the diagnosis of osteoporosis and osteomalacia.