Major controversy exists regarding the preferred treatment option for acute kidney injury (AKI). The purpose of this study was to assess the incremental cost-effectiveness of continuousrenal replacement therapy (CRRT) versus intermittent renal replacement therapy (IRRT) and conservative (CONS) AKI treatment in Belgium. An area-under-the-curve model based on survival analysis was used to estimate costs and health outcomes using a 2-year time horizon. Input data were derived from the multi-centre Stuivenberg Hospital Acute Renal Failure 4 study. Analyses indicated that in-hospital mortality, hospitalization costs and hospital length of stay differed significantly between treatment modes. Follow-up mortality rates and follow-up cost per day showed no significant difference between the treatment modes. Utility values, which improved gradually after admission to the hospital, revealed no significant differences between the three treatment strategies. CONS treatment was associated with a 2-year cost of 33 802Euro and 0.54 quality-adjusted life years (QALYs). The CRRT was the most expensive therapy with a cost of 51 365Euro leading to 0.57 QALYs. The cost and QALYs associated with IRRT were 43 445Euro and 0.50, respectively. One-way sensitivity analyses indicated the oin-hospital mortality' as the variable with the greatest influence on the results. Probabilistic sensitivity analysis resulted in a significant difference in treatment costs but no significant difference in QALY gain. This study has indicated that the most expensive treatment (CRRT) associated with an incremental cost of approximately Euro7920 generates only a minor non-significant increase in QALYs of 0.07 compared with IRRT. Additionally, the results revealed that the RRTs did not result in a significant increase in QALYs despite their higher cost compared with the CONS treatment. From a health economic perspective, the latter seems to be the preferred treatment strategy.