The UPCI practices water baptism as a necessary component of salvation — not merely as a symbolic ordinance performed after conversion. Baptism must be administered by full immersion in the name of 'Jesus Christ' (or 'the Lord Jesus Christ' or 'Jesus'), not in the Trinitarian formula of 'Father, Son, and Holy Spirit.' The UPCI holds that the command of Matthew 28:19 is fulfilled by the name 'Jesus,' since that name encompasses the fullness of God. Baptism using the Trinitarian formula is considered invalid and must be redone.

This Jesus-name-only baptism is the most practically distinctive feature of UPCI practice and the primary reason Trinitarian Christians who join the UPCI must be rebaptized. The UPCI regards this as not a minor technicality but a matter of doctrinal and salvific importance: baptism in Jesus' name applies the blood of Christ and is the moment of forgiveness, connected to the new birth.

The Lord's Supper is observed as a memorial of Christ's death — the UPCI does not hold to the Real Presence in Catholic or Lutheran terms. Bread and juice (typically unfermented) are symbolic of Christ's body and blood. The frequency of the Lord's Supper varies among UPCI congregations. Footwashing, drawn from John 13, is also practiced in many UPCI churches as a third ordinance, reflecting the humble service of Christ.