An act does not make anyone guilty unless there is a criminal intent or a guilty mind.
Actus Non Facit Reum Nisi Mens Sit Rea explains that for any act to be illegal in nature it must be done with a guilty mind. Thus to convict the defendant, it must be proved that the criminal act was carried out with a criminal intend. Not only is the act of the accused important but the intention of the accused to do the specific act is equally important to prove the guilt of the accused. Thus it can be concluded that mere commission of a criminal act or breach of law is not sufficient to constitute a crime. It should be combined with the presence of wrongful intent. Further the mens rea is important to understand the severity of the crime committed. The essential ingredient is the blameworthy condition of the mind. Its absence can negate the liability. However the statement without a guilty mind there is no crime is subjected to certain exceptions such as strict liability. Under strict liability, it is not necessary to show that a defendant possessed the relevant mens rea for the act committed.
This maxim can find its importance under section 14 of the Indian Evidence Act, 1872. It states that facts which indicate state of mind or intention are relevant facts in issue.
The two basic components of criminal law is Actus Reus and Mens Rea. Actus Reus is the wrongful act committed and Mens Rea is the state of mind behind such acts. The Latin maxim Actus Non Facit Reum Nisi Mens Sit Rea is derived from Mens Rea. Actus Non Facit Reum Nisi Mens Sit Rea further explains as to how Mens Rea is applicable in criminal law. It states that a person is guilty of a criminal act only if such acts are accompanied by a criminal intention. This maxim is used to determine whether an act committed is criminal in nature or not. Sever penal actions are required for crimes committed with specific intend and not for unanticipated or unintentional acts. However no breach of law can be left unpunished. Thus this maxim is established to differentiate between intentional and unintentional criminal act so that the quantum of punishment can be decided accordingly.
When a person is attacked by another person with an intention to cause grievous hurt or injury then it is a crime. But when the person who was attacked causes injury to the other person in private defence then it is an unintentional act. In the first scenario guilty mind was present but in the second case no intention of causing harm was there. The second act is categorised as self defence and is dealt under section 96 to 106 of the Indian Penal Code. In the first act the person is guilty of criminal act.
In the case of Brend v. Wood, Lord Goddard, C.J. held that:-
“It is of the utmost importance for the protection of the liberty of the subject that a court should always bear in mind that, unless a statute, either clearly or by necessary implication, rules out mens rea as a constituent part of a crime, the court should not find a man guilty of an offence against the criminal law unless he has a guilty mind.”
In R.Balakrishna Pillai vs State Of Kerala it was observed that “Criminal guilt would attach to a man for violations of criminal law. However, the rule is not absolute and is subject to limitations indicated in the Latin maxim, actus non facit reum, nisi mens sit rea. It signifies that there can be no crime without a guilty mind. To make a person criminally accountable, it must be proved that an act, which is forbidden by law, has been caused by his conduct, and that the conduct was accompanied by a legally blameworthy attitude of mind. Thus, there are two components of every crime, a physical element and a mental element, usually called actus reus and mens rea respectively.” Also in the case of Capt. Abdul Sattar Ahmed Pagarkar vs. R.H. Mendsonsa, Commissioner of Police the maxim Actus non facit reum nisi mens sit rea was explored. It stated that the intention behind the acts is to be understood. In the present case all the offences which were in question needed existence of an intention to commit an offence with dishonesty. These have to be dishonest intention of causing wrongful loss to the person aggrieved and wrongful gain to person who is to be the target of the investigation.
However in the case of Ranjit D. Udeshi v. State of Maharashtra the Supreme Court had held that “We do not accept the argument that the prosecution must prove that the person who sells or keeps for sale any obscene object knows that it is obscene before he can be adjudged guilty.” Thus the mens rea is not considered as important as the act committed. If the person is found having obscene material in his possession then he will be liable under sec 292 of IPC. His intention or knowledge about the obscene material need not be proved.
Edited by Vigneshwar Ramasubramania
Approved & Published – Sakshi Raje
 Brend V. Wood,  175 LT 306
 legal Service India, Mens Rea in Statutory Offences, http://www.legalservicesindia.com/article/831/Mens-Rea-in-Statutory-Offences.html (last visited May 6, 2019).
 R.Balakrishna Pillai V. State Of Kerala, Criminal Appeal No. 372 of 2001
 Capt. Abdul Sattar Ahmed Pagarkar V. R.H. Mendsonsa, Commissioner of Police, 2003 CriLJ 3790
 Ranjit D. Udeshi V. State of Maharashtra, 1965 AIR 881