BACKGROUND The aim of the study was to estimate the direct cost of an abdominal aortic aneurysm (AAA) repair and to validate it against the national Diagnostic Related Group (DRG) costs. METHODS Records from involved hospitals were used along with information on wages, cost of ICU and ward time were used to estimate the direct hospital costs including surgery-related costs up to one year after discharge from the vascular department for 75 patients who were consecutively operated for asymptomatic AAA, symptomatic AAA with and without rupture in the period leading up to March 2008. RESULTS Cost for emergency surgery varied considerably (33,069-2,842,708 DKK). Three outliers were identified. After planned repair, acute repair without and with rupture, the mean costs were 115,551 (95% confidence interval (CI): 96,841; 134,260 DKK), 259,712 (95% CI: 128,950; 390,484 DKK) and 436,127 DKK (95% CI: 172,415;669,839 DKK) (p = 0.027) and 108,969, 188,571 and 238,088 DKK excluding three extreme outliers, p = 0.009)). DRG costs for repair without and with rupture was 100,339 and 98,087 DKK, respectively. CONCLUSIONS DRG costs are not suitable for cost effectiveness analyses of screening for AAA due to a lack of classification of acute repair without rupture and underestimation of emergency costs.