Autoimmune encephalitis are a new category of inflammatory diseases of the central nervous system mediated by antibodies that attack neurotransmitter or protein receptors on the surface of neurons. The clinical syndromes are complex and are associated with manifestations that vary according to the type of antibody that is associated. The autoimmune response can start due to the presence of a tumour or viral infection, but in many case the cause remains unknown. In paediatrics, the most frequent autoimmune encephalitis is that associated with NMDA glutamate receptor antibodies (or anti-NMDA encephalitis). In children and teenagers, the initial symptoms are usually different from those of adults and the disease is rarely associated with tumours. In this article, in addition to anti-NMDA encephalitis, the general aspects of autoimmune encephalitis are reviewed and the most common questions asked about treatment of these diseases are addressed.