BACKGROUND: In patients with multiple myeloma, thrombotic microangiopathy is a rare adverse event associated with proteasome inhibitors, such as bortezomib, carfilzomib, and ixazomib. CASE PRESENTATION: Two patients with multiple myeloma who presented with carfilzomib-induced thrombotic microangiopathy received eculizumab with subsequent stabilization of renal function. CONCLUSIONS: Given the overall rarity of this adverse event, the simultaneous presentation of these 2 cases was unexpected. These cases underscores the need for heightened awareness in clinical practice of thrombotic microangiopathy. The potential role of eculizumab as a therapeutic treatment in the setting of thrombotic microangiopathy requires further investigation.