ObjectivesSurgical site infections (SSIs) after bypass procedures provoke major costs. The aim of this prospective randomised trial was to assess if preoperative duplex vein mapping (DVM) reduces costs generated by SSI. Materials/methodsPatients undergoing primary infrainguinal bypass were randomised to DVM of the ipsilateral greater saphenous vein (group A) or none (group B). Costs were calculated by the hospital’s accounting department. ResultsFrom December 2009 to April 2011, 130 patients (65 each group) were enrolled. Both cohorts were equal regarding demographics, risk factors and costs for primary bypass surgery, respectively. SSIs were classified minor (A: n = 13 vs. B: n = 13, P = n.s.) and major (A: n = 1 vs. B: n = 12, P = .0154). Preoperative DVM was the only significant factor to prevent major SSI (P = .011). Theatre costs for SSI: A: 537 € versus B 6553 € (P = .16). Recovery room/intensive care unit (ICU) costs for SSI: A: 0 € versus B: 8016 € (P = .22). Surgical ward costs for SSI: A: 2823 € versus B: 22 386 € (P = .011). Costs for outpatient visits due to SSI: A: 6265 € versus B: 12 831 € (P = .67). Total costs of patients without SSI: 8177 € versus major SSI: 10 963 € (P < .001). ConclusionDVM significantly reduces costs generated by re-admission in patients suffering from major SSI.