The aim of this paper is to give a detailed description of the so-called "chronic recurrent multifocal osteomyelitis" (CRMO). The clinical, radiological and histopathological results of an analysis of 29 cases (15 children/adolescents and 14 adults) are presented and correlated to current data from the literature. We could delinate the following points: 1. CRMO is a systemic aseptic inflammation of the bone marrow (Osteitis), it can occur polytopically and association with pustulous dermatologic symptoms is possible. 2. It is not a rare disease 3. Osteomyelitis is probably "reactive" and a plasma-cell sclerotic process with ist own characteristic histologic three-phase course. 4. We could observe 5 specific types of localization which can be documented by X-ray or bone scan. 5. Accompanying arthritis os often present, especially "sympathetic coxitis". 6. The use of drugs in treatment of CRMO (i.e. azithromycin, calcitonin, and bisphosphonates) is discussed. In conclusion we want to point out, that 1. 99mTC bone scan should always be performed when there is suspicion for CRMO to reveal the pattern of affection, 2. the rheumatologist and dermatologist should be contacted, 3. operation is normally not necessary for treatment of the mostly self-limitin disease, and 4. the term "SAPHO syndrome" should be avoided, further differentiation of the diagnosis is necessary.