The genesis of the controversy between People's Republic of Poland and the German Democratic Republic over territorial waters in the Pomeranian Bay goes back to the decisions of the Potsdam Conference and inaccuracies in later agreements and unilateral decisions of both states. In the years 1985-1989 the conflict aggravated to precedental scale in relations between allies within the Warsaw Pact. There was an actual threat that the ports of Szczecin and Swinoujscie would be deprived of free access to the Baltic Sea. In order to be able to formulate hypotheses about the reasons of the escalation of the controversy and its unexpected rapid conclusion, the conflict in the Pomeranian Bay must be viewed against a broad backdrop of Polish-East German political relations in the 1980s, taking into account the system features of the block of socialist states as well as the nature of contacts between the two German states. The stance adopted by state and party authorities in the GDR and Poland exposed the weakness of their ideology and state institutions at the decline of the communist era, evidenced by their inability to foresee its approaching end. This lack of response to impulses coming from the outside, proved fatal to the painstakingly built ideology of an independent East German state.