ANTIBIOTICS ARE FREQUENTLY prophylactically administered in surgical procedures to reduce the incidence of infection. The penetration of antibiotics into lumbar discs has been studied with mixed results, but penetration into cervical discs has not been reviewed. In this study, we examined the penetration of two commonly used antibiotics, oxacillin and cefazolin, into cervical discs. Eighteen patients with a total of 30 discs removed were studied. Two groups, each consisting of four patients with five discs removed, received either 1 g of oxacillin or 1 g of cefazolin by a single, preoperative intravenous infusion. Two other groups, each consisting of five patients with 10 discs removed, received either 2 g of oxacillin or 2 g of cefazolin, also by a single, preoperative intravenous infusion. A blood specimen, from which serum antibiotic levels were determined, was obtained from each patient simultaneously with each discectomy. The time interval between the antibiotic infusion and discectomy/phlebotomy was also recorded. Antibiotic levels were detected in all discs removed but were quantifiable in only 12. Nine of these 12 had been exposed to cefazolin. Of these nine discs, one was from a patient who had received 1 g whereas the other eight were from patients who had received 2 g of cefazolin. This represents 80% of the removed discs exposed to 2 g of cefazolin (10 discs total) and 20% exposed to 1 g (5 discs total). The remaining three discs with quantifiable antibiotic levels had been exposed to 2 g of oxacillin, which represents 30% of the discs (10 total) exposed to that dose of oxacillin. Although cervical disc space infections are rare, they are serious. This information should be considered by those using prophylactic antibiotics for invasive cervical disc space procedures.