De delictis gravioribus (Latin for "on more serious crimes") was a letter written on 18 May 2001 by then Cardinal Joseph Ratzinger, Prefect of the Congregation for the Doctrine of the Faith, to all the Bishops of the Catholic Church and the other Ordinaries concerned, including those of the Eastern Catholic Churches. The letter was published in the official gazette of the Holy See, the Acta Apostolicae Sedis, in 2001.
It covers "the more serious offences reserved to the Congregation for the Doctrine of the Faith" that the apostolic constitution Pastor Bonus of 28 June 1988 attributes to the competence of that office:
The Code of Canon Law also speaks of offences reserved to the Congregation for the Doctrine of the Faith, and likewise does not specify them.
Of the eight more grave delicts (graviora delicta) in behaviour or in the celebration of the sacraments that De delictis gravioribus specified, four concern the Eucharist:
Three concern the sacrament of Confession:
In addition, the document lists one offence of a moral character, not directly connected with administration of the sacraments, as reserved in the same way as these to the Congregation for the Doctrine of the Faith, namely, the offence of a cleric (a bishop, priest or deacon) who commits a sexual sin with someone under 18 years of age.
Reservation of these offences to the Congregation does not mean that the Congregation itself tries those accused of committing them. It requires instead that, if a preliminary investigation shows that it is at least probable that the offence was committed, the ordinary (in the Eastern Catholic Churches called the hierarch) is to consult the Congregation on the manner in which his own tribunal is to proceed. In addition, any appeals from the verdict of that tribunal are to be made to the Congregation, instead of the usual appeals tribunal.
In the case of criminal actions brought before an ecclesiastical tribunal against someone accused of offences reserved to the Congregation for the Doctrine of the Faith, prescription normally limits to ten years from the date of commission of an offence the time within which the prosecution may be initiated; but the document De delictis gravioribus lays down that, in the case of a sexual offence against a minor, the period of ten years begins to run only when the minor reaches 18 years of age.