We experienced a favorable outcome in an adult case of atypical hemolytic uremic syndrome (aHUS) after long-term eculizumab treatment. A 38-year-old Japanese man with a history of central retinal vein occlusion was admitted to our hospital with progressive dyspnea. He was found to have non-immune hemolytic anemia, thrombocytopenia, and acute renal failure two weeks after an episode of the common cold. Plasma exchange was ineffective; therefore, we initiated eculizumab after we excluded other thrombotic microangiopathies. Although long-term peritoneal dialysis was required, we successfully discontinued dialysis 18 months after the onset of aHUS with eculizumab.