Encephalitis (brain inflammation) is often thought to be mediated by infections (e.g. viral). With the advances in molecular diagnostics, new immunological markers (antibodies) are being discovered in patients presenting with encephalitic syndromes. Thus, research has evoked interest in the ‘immune theory’ of encephalitis. Limbic encephalitis (LE) was first described in the 1960s and refers to the subacute onset of episodic memory loss, confusion, and agitation. LE is frequently associated with hallucinations, seizures, sleep disturbance, and signal change in the medial temporal lobe and hippocampi on imaging. LE is classically described as being paraneoplastic. We review the clinic– pathological details of Autoimmune Encephalitis in this article.