BACKGROUND: Consensus and evidence on the impact of pre-emptive antibiotic treatment after pancreatoduodenectomy is lacking, which is reflected by contradictory recommendations in (inter)national guidelines and current clinical practice. Pre-emptive antibiotic treatment may reduce the risk of abdominal surgical site infections in patients with a high risk of contaminated bile undergoing pancreatoduodenectomy. This pertains mostly patients with preoperative biliary drainage or an ampullary malignancy. The SPARROW trial will evaluate the effect of pre-emptive antibiotic treatment in patients with preoperative biliary drainage or an ampullary malignancy undergoing pancreatoduodenectomy. METHODS: The SPARROW trial is a multicentre, open-label, randomised controlled trial evaluating the effect of pre-emptive antibiotic treatment in patients with a high risk of contaminated bile undergoing pancreatoduodenectomy. A total of 366 evaluable patients will be included in twelve centres in the Netherlands. Patients will be randomly allocated to either the perioperative antibiotic prophylaxis and pre-emptive antibiotic treatment (intervention) arm and the perioperative antibiotic prophylaxis (control) arm. In both study arms, the perioperative antibiotic prophylaxis consists of cefazolin, metronidazole and a single-dose of gentamicin, which is discontinued after surgery. In the pre-emptive antibiotic treatment arm, an additional antibiotic course of 5 days of cefuroxime and metronidazole is started postoperatively. The primary outcome is a clinically relevant organ/space surgical site infection (OSI) up to 90 days after surgery. Secondary outcomes include other clinically relevant complications (such as isolated OSI, superficial incisional surgical site infections, postoperative pancreatic fistula, ICU admission, readmission, and in-hospital and 90-day mortality), use of therapeutic antibiotics, and concordance between perioperative obtained bile cultures and cultures obtained from infectious complications. DISCUSSION: The SPARROW trial will provide evidence on the effect of pre-emptive antibiotic treatment in patients with a high risk of contaminated bile undergoing pancreatoduodenectomy to provide recommendations for an improved and standardised antimicrobial policy. TRIAL REGISTRATION: ClinicalTrials.gov NCT0578431. Registered on March 23, 2023.