Interferon-beta is widely used for the treatment of relapsing multiple sclerosis. The drug is usually well tolerated, but autoimmune adverse effects, including kidney disease, have been reported. Only a few cases of hemolytic uremic syndrome-thrombotic microangiopathy associated interferon-alpha have been described so far, and even fewer with beta-interferon. We report a patient who developed thrombotic microangiopathy during treatment with interferon-beta and improved after discontinuation and steroid therapy. Complement cascade and antiphospholipid antibodies are investigated. The spectrum of renal diseases associated with interferon-beta treatment is also reviewed.