It is divided into 20 deaneries, which in turn are divided into 136 pastoral care units. In 2007 these parish associations or parish groups included all 335 parishes and other chaplaincies of the diocese (as of 2007). Pastoral units on the parish level have been introduced as a result of a profound structural change in the Catholic Church in Germany in many dioceses, the constitution of these units was determined by particular law of a particular region or territory, i.e., allowing for differences from one diocese to another. In the diocese of Mainz a parish group may be several parishes merged under the leadership of a single pastor. The parishes retain their church and state church legal personality. The pastor is attached to a pastoral team and a pastoral council. Parish associations, however, are combinations of several parishes, each with its own pastor. Several parish groups can join together to form a parochial associations.