On the basis of the method of historical and comparative legal analysis the experience of codification of the general principles of administrative law of the CIS member states has been studied. The vast majority of codification was carried out by adopting the German model of legislative regulation of administrative procedures. The analysis of reception required the reference to its source — the German model of partial codification of the General Part of Administrative Law. As a result of the study, three models of interaction of the general principles of administrative law and their codification have been identified. The first model is marked by the development of the judicial doctrine of the general principles of administrative law and their subsequent codification. The second model is distinguished by the codification of the general principles of administrative law with the necessity of their subsequent development in the judicial and scientific doctrine. The introduction of the general principles of administrative law by borrowing a foreign codified act due to the resistance of local law, as well as the lack of judicial and scientific doctrine, can create conditions for the emergence in administrative law of a significant gap between “law in books” and “law in action”. In addition, the third model, characterised by the absence of codification of the general principles of administrative law and their differentiated regulation in sectoral laws, has been identified. It has been established that the effectiveness of the general principles of administrative law depends not only (and even not so much) on their legislative consolidation, but on the intensity and quality of judicial activism in the relevant legal system. Moreover, in some legal systems a significant contribution to the identification and development of general principles of administrative law is made by constitutional courts, in other legal systems — by administrative courts.