On 3 March 1392, Bebek was transferred to the position of Voivode of Transylvania (and thus "ispán" of Szolnok County too). He left Buda for Transylvania by April, first appeared in Kolozsvár (today Cluj-Napoca, Romania), then participated in the Diet of Torda between 6 and 12 May. Following that Bebek returned to the royal court, while the province was administered by his deputy, vice-voivode Bartholomew Szobi. He visited Transylvania again in April 1393, participating in the Diet. Whole summer, he resided in the Fortress of Déva (today in Deva, Romania) since June to prepare the military defense of Transylvania and strengthen its border against the Ottoman Empire, who launched a campaign against Bulgaria and captured Tarnovo.