Disclosed is the use of a MASP-2 inhibitory agent which inhibits MASP-2-dependent complement activation in the manufacture of a medicament for treating a subject suffering from or at risk for developing non-Factor H-dependent atypical haemolytic uremic syndrome (aHUS), wherein the MASP-2 inhibitory agent is an anti-MASP-2 monoclonal antibody, or fragment thereof that specifically binds to a portion of mature human MASP-2 protein.