Postsurgical infection has always been a cause for major concern in ENT surgery. Papers on the topic allowed to identify indications for antibiotic prophylaxis. In ear surgery, in the absence of prior infection (stapes surgery, medium dry ear surgery), studies' results are not in favour of antibiotic prophylaxis. On the other hand, however, when the ear is inflamed or infected, the use of antibiotics is indicated, if possible after having first taken a sample. For nose and sinus surgery, antibiotic prophylaxis seems to be worthless in the absence of a prolonged packing. If a packing has to be maintained or if a transplant is used, an antibiotic administration has to be considered; the most appropriate antibiotic and its mode of use still have to be specified. In case of facial trauma, antibiotic prophylaxis using cefazolin reduces the risk of infection of paraymphysis fractures and angle fractures. The postoperative course after tonsillectomy is simplified by a prolonged antibiotic administration based on ampicillin. In clean cervico-facial surgery, without buccopharyngeal opening, the antibiotic prophylaxis seems to be worthless. In the opposite, antibiotherapy is required in case of buccopharyngeal opening. Indeed the presence of potential pathogenic bacteria in the buccopharyngeal cavity, the difficulties of mucosa closing, the importance of the tumoral extension, the length of the procedure, radiotherapy and use of myocutaneous flaps may all be the cause of a high infection rate (80%) in the absence of antibiotic prophylaxis. Two types of antibiotics seem to be suitable, cefazolin and clindamycin. Antibiotics active against Gram negative bacteria seem to be useless. There is a disagreement concerning the duration of antibiotic administration. The populations studied are too small to obtain significant results. Both points of view (prolonged antibiotic administration or true antibiotic prophylaxis) can be considered. Only large scale prospective studies with an adequate methodology will provide credible data for this debate.