Name applied to two Benedictine Congregations. A Benedictine reform instituted at the monastery of Saint Justina, Padua, 1409, by Abbot Ludovico Barbo, received the title of "Cassinese Congregation" in 1504. This reform gradually spread to all the chief Benedictine monasteries in Italy, including Monte Cassino, Subiaco, Saint Paul's in Rome, Saint George's at Venice, La Cava, and Farfa. Characterized by a centralized form of government, its strength and prosperity continued until reduced by the Italian Revolution and later decrees of the Italian government.

The Cassinese Congregation of Primitive Observance was established, 1851, by Pius IX when he joined into one federation all the monasteries which took up the reform initiated at Genoa by Abbot Casaretto of Subiaco. This federation was called after its chief house, the "Province of Subiaco." Before long, monasteries in other countries adopted the same reformed observance and became affiliated to Subiaco. Besides the Italian province, the congregation includes the English province, originally founded by Saint Augustine of Canterbury; the Belgian province, dating from 1858 with the subjection of the ancient Abbey of Termonde to Subiaco; the French province, formed in 1859, with the affiliation of Pierre-qui-Vire; the Spanish province, founded in 1862 when the Abbey of Monserrat joined the congregation.

The American Cassinese Congregation (founded by Pope Pius IX, 1855), comprises 13 abbeys throughout the United States, and has for its president, Right Reverend Ernest Helmstetter, O.S.B., Abbot of Saint Mary's, Newark, New Jersey