Various archivist monks – with the title of vestararius first and then armarius – from the 13th century onwards worked diligently in the custody, study and utilisation of documents, ordering them and noting the regesto on the back.
After the period of the commendation, with the aggregation of Cava to the Congregation of St. Justina of Padua in 1497, archival studies also flourished again, thanks above all to the work of D. Vittorino Manso, D. Alessandro Ridolfi and D. Agostino Venereo, undoubtedly the most important of the latter. Agostino Venereo, undoubtedly the greatest archivist of Cava. The latter read and transunted all the documents, dividing them according to funds and places of origin, separating papal bulls and documents from private documents, wrote a summary with chronological and archival data on the back of each one, and transcribed these indications into large registers. At the same time, D. Agostino marked in several folio books all the information he considered interesting, creating dictionaries that are still irreplaceable for various historical researches. It should be made clear that the paper material remained united with the parchment material.
In 1626, new cabinets were set up, marked with letters for diplomas and with numbers for private documents. In 1760, with the demolition of the old church, the archive and library, which were housed on it, had to change location. It appears, however, that the current rooms, equipped with elegant cupboards and decorated with beautiful Pompeian paintings on the ceiling, were set up in 1784. At the time, abbot D. Raffaele Pasca and archivist D. Salvatore De Blasi were abbots, well known for unpublished archival works and for the Series Principum qui Langobardorum aetate Salerni imperarunt (Naples, 1785). A notable innovation came with the archivist D. Ignazio Rossi (1827-1831), who placed the documents in chronological order and separated the paper documents from the parchment ones. After the suppression in 1866, the monks, who remained as custodians of the material requisitioned by the State, devoted themselves to the publication of the parchment documents in the 8-volume Codex diplomaticus cavensis (precisely 1388 documents from 792 to 1065), in addition to their ordinary duties of custody and study. Between 1887 and 1890 they compiled the alphabetical index by names and subject matter of the 7760 paper documents. The archive possesses over 15,000 Latin parchments, the oldest of which dates back to 792, and 101 Greek parchments.

The archival material was all studied by D. Agostino Venereo, who drew from it three fundamental works: Dictionarium Archivii Cavensis in three volumes (copied into six volumes by D. Camillo Massaro); Additiones Archivii Cavensis in three volumes; Familiarum libri in three volumes.
The chronological catalogue of parchment material, written in Latin, is contained in eight folio volumes, one for bulls and diplomas, the other seven for private documents.
The archive contains regesti, inventories and census books of great interest. Of particular note are: Regestrum D.ni Balsami Abbatis, years 1222-1225, on parchment; Inventarium abbatis Mainerii, 1341-1359, on parchment; Liber reddituum et ecclesiarum Cavae D.ni Thomae Abbatis, 1261-62, on parchment; Regestrum D. Thomae abbatis, 1259-64, on parchment paper; Regestra D. Maynerii (4 volumes), 1341-1365, in paper; Inventarium seu quinternus terrarum nostri monasterii S. Benedicti de Salerno antiquitus, 13th-14th centuries; Inventory of S. Maria Maddalena di Bari, 16th century; Censi del Vestarario, 14th century; Liber censuum Cavae, 14th-16th centuries; Regestra D. Ioannis Cardinalis de Aragonia (5 volumes), 1475-1485; Libri visitationum (29 volumes), relating to the pastoral visits of the abbots of Cava from 1500 to 1934; 15 volumes of legal copies on parchment of documents, bulls and privileges made in the years 1503-1510; 182 volumes of notarial protocols dating from 1468 to 1801; 155 registers of the administration of the Abbey, from 1497 to 1853.

For the publication of the parchment material, some documents were already included in the works of Muratori and Ughelli, but the complete edition was devised after the suppression, in 1869 to be precise, by the Cavensis monks, who published the Codex Diplomaticus Cavensis¸ edited by M. Morcaldi, M. Schiani and S. De Stefano, vol. I, Neapoli 1873; vol. II-VIII, Mediolani-Pisis-Neapoli 1875-1893; vol. IX-X edited by S. Leone and G. Vitolo, Badia di Cava 1984-1990. The published documents number 1669, from 792 to 1080.
Two fonds came into the archive by donation in the 20th century: the Mansi fonds, donated in 1970 by Miss Eleonora Mansi of Ravello, and the Talamo-Atenolfi-Brancaccio fonds, donated in 1979 by the Marquises Talamo-Atenolfi-Brancaccio of Castelnuovo Cilento. In 2012, Prince Avv. Mario Putaturo Donati Viscido di Nocera, Honorary Deputy President of the Supreme Court of Cassation, entrusted the family archive, bound by the Superintendency of Naples, making it clear that he was not entrusting it to the state library, but to the Benedictine Abbey of the Holy Trinity of Cava, following the example of his Lombard ancestors.