The decree Christus Dominus forms a decisive stage in establishing the bishops’ mission, in outlining the true identity of the dioceses and of their shepherds. On the one hand it is presented the way that the bishop have to respect in practicing their service, and on the other hand it is expressed a clear legislative will, without omitting the indication of the way that has to be observed in revising the Code. This article underlines the double size, involved by the relationship between the bishop and the Church: with the universal Church and with the local Church that he leads. In this world, dominated by secularization, the bishop has to remain the principle of unity, who announce with authority God’s word, who celebrate the sacraments, assisted by the Holy Spirit. The decree, which has theological-pastoral content, wants to make aware the bishops about their mission and the dioceses about the dignity they are called to reach: to be part in the Church of the Christ.