In holy baptism a person is received into the membership of the Christian Church, the community of believers in Jesus Christ. Baptism is one of the two sacraments (most sacred rites) of the Lutheran Church. In a baptismal service, the person being baptised is marked with the sign of the cross, baptised with water and blessed by the laying on of hands.

In holy baptism, we obey the command that Jesus gave to his disciples before he was taken up into heaven. He said to them:

"All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptising them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything that I have commanded you. And remember, I am with you always, to the end of the age."

Matthew 28:18-20 (NRSV)

A person baptised in the Evangelical Lutheran Church of Finland joins the membership of the local parish in which area they are registered.

The Lutheran church practices infant baptism. Infants are generally baptised before they are two months old. In the baptism ceremony, they receive their Christian names. Infant baptism is often called "christening".

Also adolescents and adults can receive baptism after going through confirmation school or baptism preparation.

An important role is played by the godparents, who are there for the baptised to support them in their life and faith. Normally, at least two godparents are chosen, but with the vicar's permission also one godparent may suffice. The godparents must be confirmed members of the Lutheran Church or another church that recognises infant baptism.