The Sacrament of Holy Eucharist, also known as Holy Communion, is the third of the Sacraments of Initiation. Even though Catholics are required to receive Communion at least once per year (our Easter Duty), and the Church urges us to receive Communion frequently (even daily, if possible), Eucharist is called a sacrament of initiation because, like Baptism and Confirmation, it brings us into the fullness of our life in Christ.

The Eucharist is the source and summit of the Christian life. The term “Eucharist” originates from the Greek word eucharistia, meaning thanksgiving. The presence of Christ in the Eucharist is real, true, and substantial. By his Real Presence in the Eucharist Christ fulfills his promise to be with us "always, until the end of the age" (Matthew 28:20). 

In the celebration of the Eucharist, bread and wine become the Body and Blood of Jesus Christ through the power of the Holy Spirit and the instrumentality of the priest. This is called transubstantiation. The whole Christ is truly present -- body, blood, soul, and divinity -- under the appearances of bread and wine, the glorified Christ who rose from the dead. This is what the Church means when she speaks of the "Real Presence" of Christ in the Eucharist.

Because of the intimate connection of the Sacrament of Holy Communion to our life in Christ, we must be free of any grave or mortal sin before receiving it. If we are aware of having committed a mortal sin, we must first participate in the Sacrament of Reconciliation. The Church sees these two sacraments as connected, and urges us, when we can, to join frequent Confession with frequent Communion.