The Assyrian Church of the East affirms Matthew 28:19 as the scriptural mandate for Baptism in the name of the Trinity. Baptism is understood as a sacrament of regeneration through which the believer is united to Christ's death and resurrection. The Eastern liturgical tradition emphasizes the threefold invocation of the Trinity and the epiclesis (invocation of the Holy Spirit) over the baptismal waters.

Baptism is typically by immersion in the Assyrian tradition and is administered to believers (and to infants in families of believers). Baptism imparts the Holy Spirit and initiates the believer into the Church.