The recent literature concerning prosthesis-related infection is reviewed with respect to etiology, prophylaxis and diagnosis. Most prosthesis-related infections are initiated during operation by contamination with bacteria-carrying particles from the air as a result of dispersion of skin scales from individuals in the operating room. A small number of infections are caused by hematogenous seeding of bacteria. Glycocalyx, a slime layer produced by bacteria, plays an important role in the pathogenesis of infections, especially in the presence of biomaterial. Clean-air systems in combination with perioperative systemic antibiotics reduce prosthesis-related infections from 3 or 4 per cent to a few per thousand. The use of antibiotic-loaded bone cement is advised in high risk patients although further evaluation is needed. Physical examination of the patient, laboratory tests such as the E.S.R. and C-reactive protein, serial radiograms, isotope scanning techniques and joint aspiration can all help diagnose prosthesis-related infection. However definitive diagnosis is possible only by culturing several samples of material obtained from the interface during revision operation. A perioperative frozen section of interface tissue showing acute (more than 5 leucocytes per field) or severe chronic (more than 50 lymphocytes) inflammation is highly suggestive of sepsis.