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What is Actus Reus?

Actus reus, a fundamental legal concept, refers to the actual act or conduct that constitutes a criminal offense. It's the physical component of a crime, as opposed to the mental intent. Intrigued? Discover how actus reus shapes justice with illustrative examples ahead.
Alexis W.
Alexis W.

Actus reus is a criminal act. Most crimes have two components: mens rea (or intent) and actus reus (action). Both intent and action are normally required to find a person guilty of a crime under US Criminal law doctrines.

This term is Latin, and means "the guilty act." Actus reus, by definition, means that there must be an action or physical movement. In other words, it is the overt physical action that makes a person liable for a crime. This is always required in the United States for the commission of a crime, since a person cannot be found guilty of thinking criminal thoughts or wishing that a crime would take place.

Possessing illegal drugs is an act.
Possessing illegal drugs is an act.

Common law defines an act as a voluntary or involuntary bodily movement. Nevertheless, under the Model Penal Code, which has been adopted in whole or in part into the criminal law of many US states, the act must be voluntary. It excludes from punishment acts that are caused by a reflex or convulsion, acts that occurred while unconscious or asleep, acts that occurred under hypnosis, and other bodily movements that are not intended by the actor. These exclusions protect a person from being found guilty of a crime based on action that was not under his or her control.

A person mailing a letter can be actus reus if is part of a crime.
A person mailing a letter can be actus reus if is part of a crime.

The concept of actus reus is derived from English common law. Under these principals, an act alone did not make a person guilty of committing a crime — both the illegal action and the illegal intent were required. These principals are important, since a person must both intend to commit a crime and actually take steps toward committing the crime in order to be guilty in the eyes of the law.

An act doesn't necessarily have to be a physical action, but can also be an omission or the act of possessing something. For example, if a person is required to act under the law and fails to do so, the failure can be what is required for a crime. Voluntarily being in possession of an illegal substance, such as a drug, can also be considered an "action."

Under certain circumstances, an act can be made criminal because of the intent behind it. For example, mailing a letter is normally not a criminal action, but if the letter is mailed as part of conspiracy to commit fraud, it can become an illegal action, and constitute the actus reus for the crime.

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Discussion Comments


Actus reus and mens rea walk hand in hand in order for an act to be classified as a crime. As is stated above, the actus reus is the action done and the mens rea is the thought of having the action done without actually executing the thought.

Consider it as something being premeditated then doing the act for one's own satisfaction, for whatever reason it may be: greed, envy, spite, hatred. You name it


Actus Reus is the actual act performed. For instance, I got into my car, and drove it into another person causing bodily harm or I pulled the trigger on a gun that caused injury to another.

Mens Rea: is the intention. If I meant to cause harm, I would meet the mens rea requirement. If it was an accident, as in the example of a person walking into traffic, I wouldn't have the mens rea necessary for that crime.

Prosecutors have to prove both to get a conviction. The mens rea and the actus reus elements for the crime.


@christym: According to an August 27, 2010 document regarding the Ohio Supreme Court, “Whenever a defendant is prosecuted and tried for a crime, the prosecutor must prove both that the defendant engaged in statutorily prohibited conduct” is actus renus.

On the other hand, “that the defendant had a specific mental state in violating that statue” is mens rea.

Under Ohio law, there are four mental states: negligently, recklessly, knowingly, and intentionally.


Can someone explain actus reus vs mens rea? I am not sure that I understand the difference.

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    • Possessing illegal drugs is an act.
      By: jedi-master
      Possessing illegal drugs is an act.
    • A person mailing a letter can be actus reus if is part of a crime.
      By: tab62
      A person mailing a letter can be actus reus if is part of a crime.