Thrombotic microangiopathy (TMA) associated with hematopoietic stem cell transplantation, remains a difficult complication due to its high mortality rate, lack of standardised diagnostic criteria, and limited treatment options. Although the etiology of the disease is not clear, medications, radiotherapy, graft-versus-host disease (GVHD), angioinvasive fungal, viral infections and complement activation have been implicated. Agents such as therapeutic plasma exchange (TPE), steroids, rituximab, defibrotide, eculizumab are used in its treatment. The use of treatments such as TPE, steroids, defibrotide, and rituximab did not yield satisfactory results in transplant-associated TMA (TA-TMA). Recent studies have reported successful results with eculizumab in the treatment of TA-TMA. As there is no standard dose for eculizumab in the treatment of TA-TMA, doses used in atypical hemolytic uremic syndrome (aHUS) were administered. In this paper, we present a case that was unresponsive to TPE and steroids, but which was successfully treated with eculizumab.