A Catholic litany is an extended prayer in which a series of brief invocations is followed by an unvarying response — one of the most ancient forms of Christian prayer, found in Scripture itself (Psalm 136, where the refrain ‘for His mercy endureth forever’ follows each verse).
Each litany below is presented in its full approved text, with the apostolic see's approval cited and primary-source URLs to vatican.va or to the religious orders that custodian the devotion. Many carry indulgences; see the note on each page.
Daily as a Marian devotion; traditionally chanted in many parishes during the month of May (Marian month) and October (Month of the Rosary); often added at the end of the Rosary.
All the Saints in Heaven (foundational liturgical litany)
Approved by: The most ancient of the Catholic litanies
At the Easter Vigil; at ordinations and religious professions; in litanic processions; in times of crisis or great need (this is the litany traditionally used to invoke heavenly aid in plague, war, and emergency).
Approved by: Pope St. John XXIII (February 24, 1960), for use throughout the universal Church
Especially during July (the Month of the Most Precious Blood); on the First Friday of each month in association with the Sacred Heart; before the Blessed Sacrament; for the souls in purgatory.
Especially in January (Month dedicated to the Holy Name); on the Feast of the Holy Name of Jesus (January 3); whenever blasphemy or the misuse of God's name is heard, as an act of reparation.