Objective <p>This study aims to evaluate the clinical significance of multiple intraoperative sterilizations and bacteriological surveillance in reducing postoperative intracranial infections during transnasal endoscopic skull base surgery.</p> Methods <p>This study collected clinical data from 1002 patients undergoing transnasal endoscopic skull base surgery between January 2016 and January 2024. Patients were divided into a routine sterilization group (367 patients) and a multiple sterilization group (635 patients) based on the sterilization method. The rates of intracranial infections were compared between the two groups. Additionally, intraoperative bacteriological monitoring before and after sterilization was performed on some patients in the multiple sterilization group to analyze bacterial colonization and its relationship with intracranial infections.</p> Results <p>In the routine sterilization group of 367 patients, 21 patients (5.72%) developed intracranial infections. Of these, 20 patient had cerebrospinal fluid leakage during surgery. In the multiple sterilization group of 635 patients, 14 patients (2.20%) developed intracranial infections, all associated with cerebrospinal fluid leakage during surgery. Among the 96 patients who underwent bacteriological monitoring, 59 patients and 11 patients had definitive positive bacterial cultures before and after nasal disinfection, respectively. Additionally, 18 patients and 5 patients had definitive positive bacterial cultures before and after sphenoid sinus disinfection, respectively. One patient developed an intracranial infection caused by the same pathogens cultured from the nasal cavity.</p> Conclusion <p>Most pathogenic bacteria causing postoperative intracranial infections in patients undergoing transnasal endoscopic skull base surgery originate from nasal colonization. Multiple intraoperative sterilizations can reduce the incidence of intracranial infections in patients with high-risk factors for intraoperative cerebrospinal fluid leakage.</p>