Regional security is a concept that is increasingly becoming more important for understanding national and international security of a particular state. This fact makes the analysis and evaluation of security risks and threats to Republic of Croatia that are coming from its immediate surroundings necessary. Out of all the other states in the region, Bosnia and Herzegovina is a primary state of security interest for the Republic of Croatia, and thus deserves a central place in an analysis concerned with its regional security. Through analysis of existing expert literature, official documentation and public opinion, this article detects primary sources of security threats and basic guidelines of Republic of Croatia's security policy in the context of Bosnia and Herzegovina, which enables a scenario analysis of the future development of the security situation in that state. The primary conclusion of the article is that changes in the security architecture of Bosnia and Herzegovina in the future aren't likely, except in the context of potential disturbances in the global balance of power between the Great powers, and that political fragility and instability of Bosnia and Herzegovina must make developing an informed and active security policy a security priority for the Republic of Croatia