Examination of Conscience: Mortal Sins

Spread the Psalms

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