OCIA, which stands for Order of Christian Initiation of Adults, is a process through which non-baptized men and women enter the Catholic Church. It includes several stages marked by study, prayer and rites at Mass. Participants in the OCIA are known as catechumens. They undergo a process of conversion as they study the Gospel, profess faith in Jesus and the Catholic Church, and receive the sacraments of baptism, confirmation and Holy Eucharist. The OCIA process follows the ancient practice of the church and was restored by the Second Vatican Council as the normal way adults prepare for baptism. OCIA has previously been called RCIA which stood for Rite of Christian Initiation.

Prior to beginning the OCIA process, an individual comes to some knowledge of Jesus Christ, considers his or her relationship with Jesus Christ and is usually attracted in some way to the Catholic Church. This period is known as the Period of Evangelization and Precatechumenate. For some, this process involves a long period of searching; for others, a shorter time. Often, contact with people of faith and a personal faith experience lead people to inquire about membership in the Catholic Church.
After conversation with an advisor or spiritual guide, the person, known as an “inquirer,” may decide to seek acceptance into the Order of Catechumens. The inquirer stands amidst the parish community and states that he or she wants to become a baptized member of the Catholic Church. The parish assembly affirms this desire and the inquirer becomes a “catechumen.”
The period of the catechumenate can last for as long as several years or for a shorter time. It depends on how the person is growing in faith, what questions they encounter along the way, and how God leads them on this journey. During this time the catechumens consider what God is saying to them in the scriptures, what changes in their life they want to make to respond to God’s inspiration, and what membership in the Catholic Church involves.
When a catechumen and the parish team working with him or her believes the person is ready to make a faith commitment to Jesus in the Catholic Church, the next step is the request for baptism and the celebration of the Rite of Election. This rite includes the enrollment of names of all those seeking baptism at the coming Easter Vigil. On the first Sunday of Lent, the catechumens and their sponsors gather at the cathedral church and the catechumens publicly request baptism. Their names are recorded in a book and they are called “the elect.” The days of Lent are the final period of purification and enlightenment leading up to the celebration of initiation at the Easter Vigil. Lent is a period of preparation marked by prayer, study, and spiritual direction for the elect, and prayers for them by the parish communities.

The third step is the Celebration of the Sacraments of Initiation, which takes place during the Easter Vigil Liturgy on Holy Saturday when the catechumen receives the sacraments of baptism, confirmation and Holy Eucharist. Now the person is a fully initiated member of the Catholic Church.
After the person is initiated, formation and education continue in the period of the postbaptismal catechesis, which is called “mystagogy.” This period continues at least until Pentecost. During the period the newly baptized members reflect on their experiences at the Easter Vigil and continue to learn more about the scriptures, the sacraments, and the teachings of the Catholic Church. In addition they reflect on how they will serve Christ and help in the church’s mission and outreach activities

Coming into full communion with the Catholic Church describes the process for entrance into the Catholic Church for men and women who are baptized Christians but not Roman Catholics. These individuals make a profession of faith but are not baptized again.
To prepare for this reception, the people, who are called “candidates,” usually participate in the RCIA process to help them understand and experience the teachings and practices of the Catholic Church. They are accepted into full communion with the Catholic Church with Confirmation and Eucharist during the Easter season.

The process by which adults formally join the Catholic Church has traditionally been referred to as the Rite of Christian Initiation of Adults (RCIA). In November of 2021, the U.S. Conference of Catholic Bishops approved a new translation of the process and its corresponding curriculum, now known as the Order of Christian Initiation for Adults (OCIA).