After World War II, the declaration of the independent Jewish state started to be discussed again by the international community. In these days, Czechoslovakia supported the Zionist movement/Israel in new-born organization of United Nations, and also provided an unofficial assistance to the Zionist movement through the arm supplies as well as military training to chosen Jewish volunteers. This cooperation was not immediately cancelled after the February coup in 1948 when the Communist Party of Czechoslovakia got a total dominance over politics of the country. In the long run, however, the communist rule in Czechoslovakia led to the growing tension in relations with Israel. Within next few year the mutual cooperation of both states was over and the mutual relations were close to the open hostility. One of the aims of this paper is to introduce the reasons that led to a shift of Czechoslovak attitude towards Israel, as well as the impact of these changes in the international context.