The author's aim was to present the role of Transjordan and its ruler in the Palestinian conflict 1936-1948. The article was based mainly on studies concerning the history of Jordan and its policy. The state of Transjordan played an important role in the Palestinian conflict. The role was predominantly determined by the fact that the territory of Transjordan used to be part of Palestine. The emir of Transjordan, Abdullah, based his politics on subordination to Great Britain. He received British financial support and military consultation in return. They made the establishment of Transjordan possible. Abdullah wanted to expand his rule to further territories. Incorporation of Palestine could be one of the factors to reach this goal. The unification of Palestine and Transjordan under his rule was part of his plans to create 'Great Syria'. In 1947 UN set a committee to solve the Palestinian problem. It decided to divide the territory into two states: a Jewish one and an Arab one. The plan was acceptable to Abdullah, as he wanted to incorporate as much of the Palestinian territory into Transjordan as possible. Transjordanian military units crossed the Jordan in May 1948, as has been agreed with the British. Israeli attacks in the area of Jerusalem changed the plans, however. After cruel war, Israel and Jordan signed a peace agreement in 1949. The treaty conceded to Jordan the occupied Arab territories. Palestinians could not aspire to political autonomy. In 1948 the emir was proclaimed the king of Palestine. In 1950 the Hashemite Kingdom of Jordan was created. It became a state radically different than Transjordan used to be. The population, as the main loser in the war, was frustrated. One of the gravest symptoms of the new situation was Abdullah's murder in 1951. The occupation of Palestine posited Jordan in the very centre of Arab affairs, linking the country to the main problem - the Palestinian issue. The major mistake inherent in the whole conception to solve the Palestinian problem resided in the fact that Transjordan - poor and sparsely populated - had been chosen as the core of the new Arab state. The mistake was due to the British choices first of all. The policy might have succeeded if Abdullah's control over Arabs residing West of the Jordan had been exercised. They were, however, only subjected to policing by the British.