The purpose of this paper was to compare the National Security Strategy of 2002 and the 2017 National Security Strategy with the descriptive analysis method. This was done by taking the five factors present in both strategies and based on their comparison. These factors are: national interests, the international environment, major threats, risks and challenges, security objectives and areas and instruments of the security policy. The basis of the overall work is the analysis of these five factors, but in order to give a concise but useful introduction to reading such a matter, a brief overview of the changeability of the concept of national security and a brief insight into the security policy of the Republic of Croatia is given before the results are presented. The aforementioned part of the paper pointed out the reasons for comparing the documents relevant to national security as well as guidelines for analyzing the comparison of the documents that were carried out. The aim of the paper was not to draw conclusions about what are the causes of the similarities between the documents, but just to point to them. There are similarities in most of the observed categories with a fundamental exception, which is that at the time of the National Security Strategy of 2017, the Republic of Croatia was a few years a member of NATO and the European Union.