The differing provisions of Canons 152 CIC/83 and 942 CCEO regarding the incompatibility of offices became the subject of the author’s attention in this study. Therefore, he posed three research questions: first, about the ratio legis of these regulations; second, about the canonical concept of incompatibility of offices in the canonical order; and third, about the value of the provisions of canons 152 CIC/83 and 942 CCEO. Using a dogmatic-legal and comparative method, he demonstrated that the basis for such solutions is an ethical-juridical foundation expressed in the relationship between public administration and the titular of the office by virtue of canonical provision. The concept functioning in the system refers to the characteristics of offices, not the attributes of the person. The regulations existing in both the 1983 Code of Canon Law and the Code of Canons of the Eastern Churches (Canon 152 CIC/83; Canon 942 CCEO) do not have the character of invalidating laws (Canon 10 CIC/83; Canon 1495 CCEO).