Biblical Unitarians affirm the atoning significance of Christ's death: his death on the cross provides the basis for the forgiveness of sins and the reconciliation of humanity to God. The shedding of Christ's blood is treated as a genuine sacrifice that deals with human sinfulness and restores the possibility of right relationship with God. Biblical Unitarians regard themselves as fully Christian on this point — the cross is central to their faith and preaching.

The specific theological mechanics of the atonement are understood variously within the Biblical Unitarian movement. Some hold to a form of substitutionary atonement; others emphasize the moral influence and covenant-ratification dimensions of Christ's death. What is universally affirmed is that the death of Jesus is not merely an inspiring example but a real and effective act by which God provides for human redemption.

Biblical Unitarians sometimes argue that their non-Trinitarian Christology actually enhances rather than diminishes the atonement: a fully human Jesus who genuinely suffered and died is a more complete representative of humanity before God than a divine being merely appearing to die. The humanity of Jesus — his genuine creatureliness and his real mortality — is essential to his role as the representative human sacrifice.