Altar servers are important lay assistants to priests and deacons during the Mass. Among other things, they carry the cross and candles during the opening procession, carry the thurible containing incense, hold the Roman Missal for the priest when he is not at the altar, hand the bread and wine to the priest for consecration during the Liturgy of the Eucharist, assist the priest in washing and drying his hands, ring the altar bells, and assist the priest in removing items from the Altar following Communion.

Altar servers are often boys and girls. However, any adult or young person who has received their first Holy Communion is eligible and encouraged to be an altar server.