The role of the Legal advisor and his office is to advise the diocese on matters with implication in civil law. The current legal adviser is Fr. David Mutahi who is a lawyer by profession. The legal office handles all the legal issues of the Archdiocese of Nyeri.
The legal office also organizes programs to educate the faithful in civil law and the Kenyan Constitution, laying emphasis on areas that may confilct with the church law.