The period of the Postulancy is the second stage of the formation program for the aspirants to the OSJ religious life. It is a period wherein the formandi are given a year of discernment and reflection on one's religious vocation. After which, they are to decide to commit themselves into the membership of the OSJ family as a religious priest or brother; and thus, to be consecrated more intimately to God by following Christ more closely in imiation of St. Joseph and St. Joseph Marello. It is also a period of immediate preparation for the Novitiate,as required by Canon Law, the OSJ Constitutions and General Directory.

Before the postulants resided with the formandi of the Oblates of St. College Seminary in Marawoy, Lipa City. It was in 2011 that the postulants were separated from the community and resided at the Greenhouse, located at the OSJCS front lot. Then in 2012, the postulancy was transferred to the Marello Retreat House (MRH), Tagaytay City. In 2014, coinciding with the anniversary of the St. Joseph Marello's canonization, a separate house for the postulants was blessed. It is located at the back of the retreat house.