In the present paper is presented the personality of Gregory Leu, bishop of the Hussites between 1940-1949, the author insisting on his missionary activity during the Second World War in Bessarabia and Transnistria, territories which were vacated in the summer of 1941 under occupation Soviet. Strong threads, Gregory Leu will make several trips to the Bessarabian area, to which he has chosen patriotic feelings during his Ismail administration (1918-1924), visiting the city of Chisinau immediately after his liberation, then passing the Dniester to Odessa, providing religious assistance to residents of regions heavily affected by war. He will select young clergy from his diocese, forming several mission delegations, and will send them periodically to Transnistrian villages and cities without priests, where they will hold a significant pastoral activity. It will inform both its hierarchical superiors and the authorities in Bucharest, through periodic reports, about its missionary activity in the territory and about the situation of the Basarabian population, proposing some viable solutions for solving the economic and social problems, but especially those related to church life .