BACKGROUND Adequate microcirculatory perfusion is essential for the provision of oxygen to the liver following transplantation. Data from the Oxygen Persufflation in Liver Transplantation (OPAL) study (ISRCTN00167887) were analyzed from liver transplants performed at a single center to determine the role of factors affecting the hepatic microcirculation and early allograft dysfunction (EAD). MATERIAL AND METHODS Retrospective data from 116 patients from the Oxygen Persufflation as Adjunction in Liver Transplantation (OPAL) study who underwent liver transplantation at a single center were analyzed. Oxygen saturation of hemoglobin (SO₂), relative capillary hemoglobin concentration (rHb), relative tissue blood flow (rBF) using laser Doppler flow measurements, and the Oxygen-to-See (O2C) spectrometry were measured and with post-transplant allograft function were analyzed using univariate and multivariate logistic regression statistics. RESULTS Livers donors had a median donor risk index of 1.8. Most liver transplant recipients were men (60.3%), with a median age of 54 years (IQR, 23-68 years). Mean post-transplant 3-month survival was 90.5%. The EAD rate was 22.4%, the median SO₂ was 78% (IQR, 29.5-95.8%), the median rHb was 55.6 AU (IQR, 16.8-74.8 AU), and the median rBF was 110.1 AU (IQR, 35.8-406.8 AU). Multivariate logistic regression analysis showed that tissue SO₂ (p=0.01), body mass index (BMI) of the transplant recipient (p=0.002), serum alanine transaminase (ALT) of the donor (p=0.02), and portal blood flow (p=0.01) were predictive factors for EAD. CONCLUSIONS Non-invasive investigations of the liver microcirculation and hemoglobin oxygenation were shown to be predictive factors for EAD following liver transplantation.