In the Roman Curia of the Catholic Church, a congregation (Latin: Sacræ Cardinalium Congregationes) was a type of department. They were second-highest-ranking departments, ranking below the two Secretariats, and above the pontifical councils, pontifical commissions, tribunals and offices.

Originally, congregations were select groups of cardinals drawn from the College of Cardinals, commissioned to take care of some field of activity that concerned the Holy See. After the Second Vatican Council, members included diocesan bishops from diverse parts of the world who are not cardinals. Each congregation also had a permanent staff.

Each congregation was led by a prefect, who is usually a cardinal. A non-cardinal appointed to head a congregation was styled pro-prefect until made a cardinal. This practice was later abandoned.

Under the reforms of Pope Francis, the congregations were each turned into what are now known as dicasteries.

Certain curial departments have been organized by the Holy See at various times to assist it in the transaction of those affairs which canonical discipline and the individual interests of the faithful bring to Rome. Among the most important were the Roman Congregations, traditionally comprising cardinals who assist the pope in the administration of the affairs of the Church.

The Roman Congregations originated from the necessity, felt from the beginning, of studying the questions submitted for pontifical decision, in order to sift the legal questions arising and to establish matters of fact. Ecclesiastical business used to be handled by the pontifical chancery. This work, at first entrusted to the papal chaplains, was afterwards divided between the penitentiarii and the auditores, according as questions of the internal or the external forum (i.e., jurisdiction) were to be considered. Thereafter, cardinals in greater or less number were associated with them. Often, however, they were not merely entrusted with the preparation of the case, but were given authority to decide it. However, the ever-growing number of business items and the ever-increasing complexity of the issues necessitated the creation of separate, specialised administrative-legislative bodies (the administrative and legislative functions of ecclesiastical government are not as sharply separated in the Catholic Church as in a secular government with the separation of powers).

Pope Sixtus V was the first to distribute this administrative business among different congregations of cardinals; and in his apostolic constitution Immensa Aeterni Dei (22 January 1588) he generalized the idea, already conceived and partly reduced to practice by some of his predecessors, of committing one or another case or a group of cases to the examination, or to the decision, of several cardinals. By a judicious division of administrative matters, he established the permanent organization of these departments of the Curia. Immensa aeterni Dei called for the formation of 15 permanent congregations:

While the chief end of the Congregations of Cardinals was to assist the pontiff in the administration of the affairs of the Church, some of these congregations were created to assist in the administration of the temporal States of the Holy See. Immensa Aeterni Dei has since been superseded, most recently by Pope John Paul II's constitution Pastor Bonus.