Atypical Hemolytic Uremic Syndrome is a triad of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure not associated with diarrhea. It is a rare condition associated with complement disorders in about 50 percent of cases. The first line of treatment is therapeutic plasma exchange. However, because clinical response to TPE varies, an anti-complement drug, eculizumab has been tried. We report a case of atypical HUS successfully treated with eculizumab.