The use of antimicrobials reduces the incidence of surgical wound infection in oral implantology. Antimicrobial prophylaxis is indicated in all Class 2 (clean-contaminated) surgical procedures, which include sufficient blood levels at the time of bacterial contamination of dental implant and bone graft procedures. Timing and dosage are critical to the efficacy of antibiotics. Antibiotic selection is determined mainly by the bacteria which is most likely to cause an infection from the specific procedure. The authors have developed a classification and protocol that allows the dental practitioner to properly prescribe medication based on procedural, local host and systemic factors.