It has been previously established that total antioxidant capacity concentrations of blood on the first day of ischemic stroke could predict mortality. Therefore, our study objective was to determine whether total antioxidant capacity concentrations in the blood during the first week of a cerebral infarction could help predict mortality. We included severe and malignant middle cerebral artery infarction patients (affecting 50% or more of the territory in computed tomography and a score of nine or fewer points in the Glasgow Coma Scale). Serum total antioxidant capacity concentrations were determined on days first, fourth, and eighth of the diagnosis of a malignant middle cerebral artery infarction. Higher serum total antioxidant capacity concentrations at first ( 0.001), fourth ( 0.001), and eighth (P = 0.003) day were found in non-surviving patients than in surviving ones. Serum total antioxidant capacity concentrations on first, fourth and eighth day of malignant middle cerebral artery infarction had an area under curve (95% Confidence Intervals) for 30-day mortality prediction of 0.86 (0.75-0.93; 0.001), 0.87 (0.74-0.95; 0.001) and 0.79 (0.64-0.90; P = 0.004)), respectively. Thus, the potential use of serum total antioxidant capacity concentrations at any time during the first 7 days of a severe malignant middle cerebral artery infarction without thrombectomy to predict mortality was the main novel finding of our study.