In Catholic teaching, a sin is mortal when it involves:
- Grave matter
- Full knowledge
- Deliberate consent
The Catechism of the Catholic Church teaches:
“Mortal sin destroys charity in the heart of man by a grave violation of God’s law.” — CCC 1855
Below is a structured list of acts traditionally recognized as grave matter that can constitute mortal sin when committed knowingly and freely.
Sins Against God (First Commandment)
Idolatry and False Worship
- Worship of false gods
- Satanism
- Occult practices
- Witchcraft
- Sorcery
- Divination
- Consulting mediums or spirits
- Astrology used as occult guidance
- Superstition replacing trust in God
Blasphemy and Sacrilege
- Blasphemy against God
- Desecration of the Eucharist
- Receiving Holy Communion in mortal sin knowingly
- Profaning sacred persons, places, or objects
Apostasy, Heresy, and Schism
- Total rejection of the Christian faith
- Obstinate denial of Catholic doctrine
- Deliberate separation from the unity of the Church
Despair and Presumption
- Despair of God’s mercy
- Presuming salvation without repentance
Sins Against Reverence for God (Second and Third Commandments)
Misuse of God’s Name
- Perjury
- False oaths invoking God
- Serious irreverence toward sacred things
Deliberate Neglect of Sunday Obligation
- Missing Mass on Sundays or Holy Days without serious reason
- Preventing others from worshipping God
Sins Against Human Life (Fifth Commandment)
Murder and Violence
- Murder
- Abortion
- Euthanasia
- Assisted suicide
- Attempted murder
- Serious physical assault
- Kidnapping
- Terrorism
Hatred and Abuse
- Serious hatred wishing grave harm
- Abuse of spouse or children
- Scandal leading others into grave sin
Substance Abuse
- Serious drunkenness
- Drug abuse
- Endangering life through reckless behavior
Sexual Sins (Sixth and Ninth Commandments)
Adultery and Fornication
- Adultery
- Premarital sexual intercourse
- Cohabitation involving sexual relations
Sexual Immorality
- Pornography
- Masturbation
- Prostitution
- Rape
- Incest
- Homosexual acts
- Contraceptive acts deliberately frustrating conception
Abuse and Exploitation
- Sexual abuse
- Seduction of minors
- Human trafficking for sexual purposes
Sins Against Family and Authority (Fourth Commandment)
Dishonor Toward Parents
- Serious neglect of parents
- Grave disrespect toward parents
Abuse of Authority
- Corruption by public officials
- Employers defrauding workers
- Parents gravely neglecting children’s spiritual or physical welfare
Sins Against Property and Justice (Seventh and Tenth Commandments)
Theft and Fraud
- Serious theft
- Robbery
- Fraud
- Embezzlement
- Tax evasion of serious magnitude
- Exploitation of the poor
- Unjust wages
Dishonesty
- Perjury
- Serious cheating
- Corrupt business practices
Covetousness
- Deliberate greed causing grave injustice
- Envy leading to harm
Sins Against Truth (Eighth Commandment)
Falsehood and Harm to Reputation
- Serious lying causing grave harm
- False witness
- Calumny
- Detraction
- Rash judgment causing serious damage
Sins Against Human Dignity and Society
Social and Structural Evils
- Racism practiced in a gravely unjust way
- Human trafficking
- Oppression of the poor
- Participation in grave injustice
- Deliberate exploitation of vulnerable persons
Scandal
- Leading another person into mortal sin
- Public corruption of morals
The Seven Deadly Sins
The “capital sins” are roots of many mortal sins:
- Pride
- Greed
- Lust
- Envy
- Gluttony
- Wrath
- Sloth
These are not always mortal in every instance, but they become mortal when grave matter, full knowledge, and deliberate consent are present.
The Sin Against the Holy Spirit
Jesus warns about persistent refusal of grace and repentance:
“Whoever blasphemes against the Holy Spirit never has forgiveness.” — The Gospel of Mark 3:29
Traditionally this includes:
- Final impenitence
- Obstinate resistance to truth
- Refusal of God’s mercy
Important Clarification
Not every serious wrongdoing is automatically a mortal sin. Catholic theology insists that all three conditions must exist simultaneously:
- Grave matter
- Full knowledge
- Deliberate consent
Mental illness, ignorance, fear, coercion, addiction, immaturity, or diminished freedom can reduce personal culpability.
For authoritative teaching, see:
- Catechism of the Catholic Church §§1854–1864
- The Holy Bible