What is a mortal sin?
According to the Catholic faith
Three things are necessary for a sin to be mortal: 1) Serious matter (listed in this section); 2. Knowledge or firm belief that the act is seriously wrong prior to committing the act; 3. Full consent of the will.
All three of these conditions must be present simultaneously for a sin to be mortal. This means that if you did not know the act was seriously wrong, then you are not guilty of having committed a mortal sin.
Examples of mortal sin:
1) I am the Lord your God. You shall not have strange gods before Me.
- Involvement in occult practices, e.g., witch-craft, ouija boards, seances, palm reading, tarot cards, hypnotism, divination, astrology, black magic, sorcery, etc.
- Involvement in or adherence to New Age or Eastern philosophies, atheism or agnosticism
- Apostasy (leaving the Church)
- Adherence to a schismatic group
- Putting faith in superstition, e.g., horoscopes, good luck charms, etc.
- Joining the Masons or other secret society
- Receiving Holy Communion in the state of mortal sin
- Receiving the Sacraments of Confirmation or Matrimony while in the state of mortal sin
- Willful participation in illicit (non-emergency) “General Absolution” services
- Being married by a Justice of the Peace or by a minister of another denomination (without dispensation)
- Involvement in false or pagan worship
- Willfully denying the Faith of the Catholic Church
- Despair of God’s grace or mercy
- Presumption (committing a mortal sin with the idea that you can just go to confession)
- Hatred of God
- Simony (buying or selling spiritual things)
- Failure to receive Holy Communion at least once per year (if possible, during the Easter Season)
- Desecration of the Holy Eucharist
2) You shall not take the Name of the Lord your God in vain.
- Using God’s Name intentionally as a curse
- Seriously wishing evil upon another
- Serious slander or insult of a sacred person or object
- Making an oath in a secret society
- Telling a lie or withholding a serious sin in confession
- Blasphemy (words of hatred, reproach or defiance toward God; speaking ill of God)
- Perjury (lying under oath)
- Swearing false oaths
3) Remember to keep Holy the Lord’s Day.
- Missing Mass on Sunday or a Holy Day of Obligation without a serious reason
- Doing unnecessary work on Sunday for a long period of time, i.e., more than several hours
- Intentional failure to fast or abstain on appointed days
- Requiring employees to work on Sunday in non-essential occupations
4) Honor your father and mother.
- Serious failure to care for aged parents
- Serious neglect of the duties of one’s state in life
- Serious disrespect for or disobedience to parents, superiors or authorities
- Wishing death or evil on parents
- Abuse or serious neglect of children
- Failure to baptize children in a reasonable time (within a few months) after birth
- Serious neglect of the religious education or upbringing of children
- Failure to carry out the last will of deceased parent
5) You shall not kill.
- Murder, homicide or manslaughter
- Procurement of an abortion
- Promoting, counseling or paying for an abortion
- Knowingly voting for someone who is pro-abortion
- Willfully injuring or trying to hurt another person
- Willfully leading another into serious sin
- Driving dangerously or recklessly
- Driving under the influence of drugs or alcohol
- Willfully harboring hatred for another
- Taking or selling illegal drugs
- Willful drunkenness
- Self-mutilation
- Excessive tattoos
- Excessive body piercing
- Piercing of the nipples or sexual organs
- Sterilization
- Promotion of or involvement in euthanasia
- Serious entertainment of suicidal thoughts
- Attempting or intending suicide
- Willful failure to bury the body or ashes of the dead
- Willful engagement in unjust lawsuits
- Bigotry (hatred for persons of other races)
- Intentionally placing temptation before the weak
6) You shall not commit adultery.
- Adultery
- Fornication (intercourse prior to marriage)
- Masturbation or other impure acts with self
- Homosexual acts (any act that limits pro-creation)
- Using a contraceptive
- Dressing or acting in a manner intended to cause arousal in another (spouses excepted)
- Kissing or touching another passionately for the purpose of arousal (spouses excepted)
- Allowing another to kiss or touch you in a sexual manner (spouses excepted)
- Intentionally causing a sexual climax outside of intercourse
- Onanism, i.e. intentional withdrawal and non-vaginal ejaculation
- Flagrant immodesty in dress
- Bestiality (sexual acts with animals)
- Oral sex (permitted as foreplay in marriage)
- Anal sex or other degrading sex practices
- Prostitution
- Rape
- In-vitro fertilization or artificial insemination
- Surrogate motherhood
- “Selective reduction” of babies in the womb
- Types of fertility testing that involve immoral acts
- Involvement in or support of human cloning
- Willful divorce or desertion
- Incest
- Polygamy or polyandry (many wives/husbands)
- Cohabitation prior to marriage
- Destroying the innocence of another by seducing or introducing them to immorality
- Lust in the heart (“if I could I would”)
- “Swinging” or wife swapping
- Transvestism or cross-dressing
7) You shall not steal.
- Stealing a large amount of money or a valuable item
- Willfully destroying or defacing another’s property
- Stealing something consecrated to God or from a Holy place
- Buying, selling, receiving or concealing items known to be stolen
- Willful failure to make restitution
- Excessive gambling
- Defrauding workers of their wages
- Serious failure to fulfill work requirements
- Padding expense or per diem accounts
- Taking advantage of the poor, simple, inexperienced or less fortunate
- Denying help to the poor, needy or destitute when able to help them easily
- Defrauding creditors
- Bribery or taking bribes
- Blackmail
- Fraud or embezzlement
- Price fixing
- Tax evasion
- Forgery
- Excessive waste or expense
- Violating copyrights
- Pirating computer software
- Slavery
- Serious cruelty to animals
8) You shall not bear false witness against your neighbor.
- False witness (not under oath) or perjury (under oath)
- Telling large or premeditated lies
- Serious gossip, detraction (revealing the faults of another without serious reason), or calumny (harming the reputation of another by falsities)
- Violation of a confidence without good reason
- Being an accomplice to another’s grave sin
9) You shall not desire your neighbor’s wife.
- Viewing pornography in books, magazines, movies, the internet, etc.
- Reading sexually explicit materials
- Dwelling on impure thoughts or fantasies for the purpose of arousal
- Willfully lusting after another
10) You shall not desire your neighbor’s goods.
- Serious and willful greed or avarice
- Intention to steal or destroy the goods of another
Catholic Church – Copyright 2002 @ Leaflet Missal Company
