The thrombotic microangiopathies (TMA) are a heterogeneous group of disorders, characterized by microangiopathic haemolytic anaemia with red cell fragmentation, thrombocytopenia and signs of organ dysfunction due to disturbed microcirculation. Current laboratory methods can be used to better distinguish some of these entities. Organ dysfunction can be severe and life-threatening, and immediate start of sufficient therapy is necessary to avoid permanent damage or death. The therapeutic options, however, are often limited to symptomatic measures, and are not standardized or based on high scientific evidence. During the preceding years, not only considerable progress has been made in better diagnosis of TMA, but also new therapeutic strategies have been established. Initial treatment still is based on plasma exchange and symptomatic measures to protect organ function. New concepts (immunosuppression, targeted anti-von Willebrand factor or anti-complement therapy, replacement with recombinant enzymes) are discussed in this article.