For ten long years, the Catholics of San Agustin begged for a resident parish priest. In March 1966, Fr. Lionell Lacasse, MS took residence there with Fr. Paul Douillard, MS. After a year, they constructed a convent. It was blessed by Fr. Maurice Cardinal, MS, then the Vice Provincial Superior of the Missionaries of Our Lady La Salette.

In April 1967, the town was officially erected as a parish by then BishopTeodulfo Domingo, D.D. of Tuguegarao, Cagayan with Fr. Lionell Lacasse, MS as the first Parish Priest. Fr. Lacasse stayed there until the end of May 1969. Two months later, Fr. Andre Lussier, MS was assigned in the parish. He stayed there for 5 years. After he left, San Agustin did not have a parish priest nor any permanent resident priest to take care of the spiritual needs of the people. The catechetical program and other projects of the parish, however, were continued by lay leaders until La Salette Regents were assigned there to assist them.

The catechetical program and other projects of the parish, however, were continued by lay leaders until La Salette Regents were assigned there to assist them.

The presence of the La Salette Regents in the parish greatly helped in the revitalization of the Parish programs and projects. Bible services were introduced and catechetical instruction was extended to nearby barrios with the assistance and cooperation of lay leaders. This contributed to the strengthening and reawakening of the Catholic Spirit in the parish.

From then on, the on-going programs of the parish had been successfully carried on through the collaboration of the priests and the empowered lay leaders together with the religious sisters who were also assigned in the parish.

(The administration of the parish was officially turned over to the Diocese of Ilagan Easter Sunday of 2006.)

San Agustin Parish was served by the La Salette Missionaries from the nearby parish of Our Lady of the Holy Rosary Parish of Jones, Isabela.

The last who served were Fr. Eugene Flores, MS and Bro. Henry Siat, MS.