Today there are an estimated 5 million members in the Legion of Mary worldwide. Requirement for membership is that one is a practising Catholic, over 18 years of age and has a willingness to abide by the Legion system which is modelled on that of the Roman Army. There two grades of membership: Active and Auxiliary.

Active Membership

To be an active member in the Legion of Mary, one must be a practising Catholic. Active members serve God under the banner of Mary by practising the Spiritual Works of Mercy. The main apostolate of the Legion consists in activities directed towards all men and women, young and old, rich and poor as well as people from the margins of society (homeless, prostitutes, prisoners etc.) and towards non-Catholics. The members of the Legion are primarily engaged in the performance of the Spiritual Works of Mercy rather than works of material aid (which are prohibited).

Additional Grades of Membership

In addition to the ordinary active membership, the Legion recognises three other grades of membership:-

Auxiliary Membership

This is the ‘left wing’ of the Legion's praying army. Its service consists in the daily recitation of the prayers comprised in the tessera, namely: the invocation and prayer of the Holy Spirit; five decades of the rosary and the invocations which follow them; the Catena; and the concluding prayers. This membership is open to priests, religious and lay people who are unable or unwilling to assume the duties of active membership, but who associate themselves with the Legion by undertaking a service of prayer in its name. There are no age limits in the case of auxiliary membership.

The Praetorians

This is a higher grade of active membership, consisting of those who to the ordinary obligations of membership undertake to add:-

• The daily recitation of all the prayers comprised in the Tessera of the Legion;
• Daily Mass and daily Holy Communion.
• Daily recitation of an Office approved by the Church, especially the Divine Office or a substantial part of it, for example Morning and Evening Prayer.

Adjutorians

This is the ‘right wing’ of the praying Legion. It comprises those who will

• recite daily all the prayers of the tessera and in addition
• agree to attend Mass and receive Holy Communion daily,
• recite daily an Office approved by the Church.

Junior Membership

Catholics aged 18 years and under can join a Junior Praesidium. There is no minimum age requirement, however children are required to attend a weekly meeting lasting an hour and perform some active work such as visiting a nursing home, helping with household chores, etc. It is a great way of training young Catholics to get involved in the works of mercy from an early age.