&NA;For the past 5 years at Mount Sinai Hospital, an intraoperative prophylactic antibiotic regime consisting of intramuscular gentamicin or tobramycin, intravenous vancomycin, and streptomycin irrigating solution, with no preoperative or postoperative antibiotics, has provided complete protection against operative infections in neurological surgery. There have been 1732 major clean operative cases with no instance of operative infection and no complication due to the antibiotics.