Membership is open to all baptised Catholics. After visiting a Praesidium a few times, one can join the legion as a probationary member for three months. Then, a decision is made on whether to join the legion as an active member permanently. During the probationary period, probationary members learn about the legion system by reading the Handbook of the Legion of Mary and its active works by listening to reports of active works undertaken by fellow legionaries. At the end of probationary period, members say an oath of "Legion promise", a pledge of allegiance to the Holy Spirit and to Mary, and become apermanent active members.
Membership in the Legion of Mary is essentially based on discipline and commitment. Members devote their time and prayer for the intentions of Mary, Mother of God.
Members can withdraw from the Legion by informing the president of his or her praesidium.
Types of Membership
The Legion of Mary consists of two totally-different memberships, active and the auxiliary members. Both are essential to the Legion: "Just as a bird cannot fly without one wing, so also the Legion cannot exist without any of the other members," said Ráinel Lobo of Mumbai, India.
Active members regularly attend the weekly sessions of their Praesidium and pray daily the prayer of the Legion, the Catena Legionis, which consists essentially of the Magnificat and some shorter prayers. Their main role lies in active apostolate for the legion and the church. Active members under 18 are not allowed to give the "Legion promise" until that age. They are considered Juniors and may hold any office except President in their Praesidium. Above the level of the Praesidium, no Junior may serve as an officer.
Auxiliary members support the legion through their prayer. They pray the whole booklet of Legion prayers, the Tessera, every day. The Tessera consists of the Invocation, prayers to the Holy Spirit, the Rosary, the Catena, and the concluding prayers of the Tessera.
Praetorians, a higher grade of active membership, pray, in addition to their duties as active members, the Rosary, the Divine Office and go to Holy Mass daily.
Adjutorians, a higher grade of auxiliary membership, additionally pray the Divine Office and go to Holy Mass daily.
Praetorians and Adjutors do not have higher status or higher rank inside the legion system. The meaning of the grades is only a desire for a more devotional life, not for higher status. Entering the grade is done by registering with a list of Praetorians/Adjutors and by subsequently observing their duties.