Antibiotic prophylaxis in oral and maxillofacial surgery aims the prevention of the infection of the surgical wound, either due to the characteristics of the surgery or the general state of the patient. This risk increases with the contamination of the surgical operation area, making it necessary to imply a prophylactic treatment of the infection in clean-contaminated and contaminated surgeries and treatment of the infection in dirty surgeries. Moreover, a proper surgical technique helps to reduce the development of the postsurgical infection. The elective antibiotic chemotherapy ranges from penicillin-derivates with betalactamase inhibitors (amoxycillin-clavulanate, ampicilin-sulbactam) to second or third generation cephalosporins, quinolones or clindamycin. The indication for the use of these antibiotics depends on the type of surgery in oral and maxillofacial surgery, according to the degree of contamination. Thus in oral surgery and surgery of the salivary glands the literature demonstrates that there is not a better prognosis when using prophylactic antibiotherapy instead of not using it in healthy patients. In traumatology this prophylaxis is justified in compound fractures and those communicating with paranasal sinuses. En orthognatic surgery there is disagreement according to the criteria of using antibiotic prophylaxis, but short term treatment is preferred in case of using it. In oncological surgery it has been demonstrated the reduce in incidence of postsurgical infection using prophylactic peroperative antibiotherapy, mostly in those cases in which oral mucosa and cervical area contact.