We describe the case of a patient with adenocarcinoma of the colon treated with FOLFOX-4 (5-Fluorouracil, Folinic acid, Oxalyplatin), with subsequent appearance of atypical hemolytic uremic syndrome (aHUS). From 1999 to 2009, 13 cases of atypical HUS receiving chemotherapy with oxaliplatin have been described, as well as some sporadic cases. None of these cases has been treated with eculizumab. This is the first report of a patient with aHUS secondary to Oxalyplatin treated with Eculizumab. This treatment induced a complete remission of the syndrome and, later on, it has been discontinued with clinical and laboratory permanent remission. We identified some genetic mutations in this patient that might have a pathogenic role in the determining aHUS when associated with exposure to Oxalyplatin. Oxalyplatin withdrawal and its replacement to Irinotecan allowed the patient to receive first line chemotherapy continuation (FOLFIRI) with the same life expectancy and the same symptoms free period.