peccatum mortale
Mortal Sin
A grave sin committed with full knowledge and deliberate consent, which destroys charity in the soul and, unrepented, leads to hell; forgiven in Confession.
deadly sin
For a sin to be mortal three conditions must all be met: the matter must be grave (the Ten Commandments are the reference point), the person must know it is gravely wrong, and they must choose it freely and deliberately. Mortal sin turns the heart away from God and results in the loss of sanctifying grace. If it is not repented and forgiven it excludes a person from the Kingdom. Anyone aware of mortal sin must go to Confession before receiving Communion. The Catechism adds that unintentional ignorance and strong passion can diminish or remove the guilt.
Not to be confused with Venial Sin.
Councils
Where the Church settled or debated this. Follow a council to read our article on it, or the decrees themselves.
- 1545–1563Council of Trentthe decrees
Sources checked 29 September 2026