Presbyter is, in the Bible, a synonym for bishop (episkopos), referring to a leader in local church congregations. In modern Eastern Orthodox usage, it is distinct from bishop and synonymous with priest. Its literal meaning in Greek (presbyteros) is "elder".

Through the sacrament of holy orders, an ordination to priesthood is performed by the bishop. But this requires the consent of the whole people of God, so at a point in the service, the congregation acclaim the ordination by shouting "Axios!" ("He is worthy!").

Orthodox priests consist of both married clergy and celibate clergy. In the Orthodox Church a married man may be ordained to the priesthood. His marriage, however, must be the first for both him and his wife. He may not remarry and continue in his ministry even if his wife should die.

If a single, or unmarried, or celibate, man is ordained, he must remain celibate to retain his service. A celibate priest is not necessarily the same as that of clergy who are monastics, as celibacy does not automatically entail monasticism, though Orthodox monasticism does denote a call to celibacy. A priest-monk is called a hieromonk.

It is church doctrine that the priesthood must strive to fulfill the grace given to them with the gift of the "laying on of hands" in the most perfect that they can. But the Church teaches that the reality and effectiveness of the sacraments of the church, ministered by the presbyters, do not depend upon personal virtue, but upon the presence of Christ who acts in his church by the Holy Spirit. The same as with bishops, it is Christ, through his chosen ministers, who acts as teacher, good shepherd, forgiver, and healer. It is Christ remitting sins, and curing the physical, mental and spiritual ills of mankind. The priest is an icon of Christ.

Priests normally exercise the function of pastors of parishes, a function which was normally done by the bishops in early times. They are rectors of the local congregations of Christians. They preside at the celebration of the liturgy and teach, preach, counsel and exercise the ministries of forgiveness and healing.

Since the presbyters are assigned by the bishop and belong to the specific congregations they have no authority or services to perform apart from their bishop and their own particular parish community. On the altar table of each parish, there is the cloth called the antimension signed by the bishop, which is the permission to the community to gather and to act as the Church. Without the antimension, the priest and his people cannot function legitimately.

The earliest organization of the Christian churches in Judea was similar to that of Jewish synagogues, who were governed by a council of elders (presbyteroi). In Acts 11:30 and 15:22, we see this collegiate system of government in Jerusalem, and in Acts 14:23, the Apostle Paul ordains elders in the churches he founded. Initially, these presbyters were apparently identical with the overseers (episcopate, i.e., bishops), as such passages as Acts 20:17 and Titus 1:5,7 indicate, and the terms were interchangeable.