The aim of the study is to analyse Poland's security and defence policy and its significance for the defence of NATO's eastern flank. A special focus of the report are changes introduced over the past two years, i.e. after Russia's illegal annexation of Crimea, NATO's actions to strengthen the eastern flank and the change of power in Poland in 2015. Even though the new government and president rhetorically have stressed the need for change, the Polish security and defence policy shows a high degree of continuity. The new regime has, however, taken several initiatives for reforms that can have an impact in the longer term. The defence budget has increased from 2016 and the Defence Minister has proposed the establishment of a new territorial defence structure as well as a revision of the military modernization program. Another important new feature is an ambition to play a greater role as a security provider, both on NATO's eastern and southern flank. Poland plays a central role in strengthening the defence of NATO's eastern flank. It hosts several important NATO installations. However it is Poland's geographic location rather than the country's national military capability that makes the country a key factor. Poland has problems with the implementation of the ongoing defence reform as well as the modernisation of equipment. At the same time, there is large support among both politicians and in the public opinion to focus on defence. If the government succeeds in realizing the reforms proposed, Poland's military contribution to the defence of the eastern flank could increase.