The C5 inhibitor monoclonal antibody, eculizumab, has been approved for the treatment of atypical hemolytic uremic syndrome (aHUS) and paroxysmal nocturnal hemoglobinuria (PNH); however, the efficacy and safety of this drug in treating other complement-related renal diseases has not yet been elucidated. The high cost of eculizumab therapy and the rare adverse effects have created a paradox in conducting large clinical trials. Therefore, there is a need to increase clinicians’ awareness of the available data on the efficacy/safety of this drug in treating renal diseases. Herein, we have reviewed the outcomes of the administration of eculizumab in aHUS, PNH, lupus erythematosus nephritis, C3 glomerulonephritis, IgA nephropathy, and antibody-mediated rejection (AMR) in highly sensitized patients. Initial findings suggest its efficacy in treating acute injuries but lower effectiveness in preventing chronic lesions. Besides, early diagnosis and timely initiation of eculizumab are of particular importance.