The paper focuses on how the Latin liturgical prayers dealt with the different Latin biblical translations, Old Latin and Jerome’s translations and revisions, from the 5th up to the 12th century. Many studies on the spreading of Jerome’s translations have focused on Latin Bible manuscripts or fragments, the Latin Fathers’ quotations of the Bible, and the Latin lectionaries’ quotations of the Bible. The present study chooses to survey the liturgical books of prayers, specifically the Twelve Prophets’ translations; while the corpus is not a big one, it offers noteworthy results. First presented are quotations or mentions of a Latin verse where translation is identical in the Vetus Latina and the Vulgate. Then cases where Vulgate is used and cases where Old Latin is used are analyzed. It is not always easy to identify the translation used in the liturgical book, and one can sometimes only compare different assumptions on biblical-inspired liturgical texts to know whether its source is Old Latin or Vulgate. Moreover, translations of an Old Testament verse and a New Testament one are sometimes interfering. This happens mainly when the New Testament verse, while quoting the Old Testament one, retains the Old Latin translation, even in the Vulgate version. Samples of verses whose Old Latin survived Jerome’s translation are provided. The paper shows how one liturgical book can draw on both Old Latin and Vulgate, even within the same item, and stresses the need for a detailed analysis, liturgical book by liturgical book, to study the quotations from the Bible in the Latin liturgy.