In this Article an attempt has been made to analyse Section 84 Indian Penal Code which deals with the defense of insanity in criminal law. ‘Insanity’ is a word that does not have any precise definition, however , broadly it refers to the varying degrees of mental disorder. In Section 84 instead of the word ‘insanity’ the term ‘unsoundness of mind ‘ is used to broaden the scope of the word. This Section is mainly based on the famous Rule of M’Naghten evolved by the English Courts and hence in this Article brief mention of the M’Naghtens rule is made. To provide an accused the benefit of Section 84 it must be proved that at the time of commission of the offence his cognitive faculties were so impaired that he was not capable of knowing the nature of the act . Section 84 was subject to a number of interpretations in the various decisions of the Courts which throw important light on the various words used in this section. In this Article those case laws are being dealt with.
