The article deals with the issue of dangers and opportunities in the development of the Warmia and Mazury region in the context of being in the neighbourhood of the Kaliningrad region of the Russian Federation. The aim of the article is to present selected conditions of functioning of the Warmia and Mazury region as a border region neighbouring the Kaliningrad region of the Russian Federation, as well threats related to the military potential of the Kaliningrad region. The border location of the Warmia and Mazury region deepens its peripherality both from the point of view of economic development and its influence on the policy of the Polish central authorities. A significant barrier to the development of the region was the introduction of the visa regime on the Polish-Russian border before Poland’s accession to the European Union. Another factor in cross-border relations was the introduction of the local border traffic mechanism, which facilitated border crossings from 2012 to 2016. Since 2014, Polish-Russian relations have been deteriorating at the political level. This has made it necessary to treat the Kaliningrad region as a potential source of danger to Poland. The Russian invasion of Ukraine, launched in February 2022, further aggravated this trend.