Beside conventional radiology and bone scintigraphy, an important role is played in the diagnosis of osteomyelitis by sonography (US). This technique is especially useful to detect fluid collections in the soft tissues adjacent to the bone. Ten patients with osteomyelitis were examined: in 8 cases the presence of fluid collections was demonstrated, which were sometimes spreading along the bone axis and sometimes localized in a single site. The collection was subperiosteal in all cases. Sonography proved thus useful in providing further information on the bone affected with osteomyelitis.