In 1934 he returned to Warsaw University as a full professor. Until the start of world War II , he was active in research and teaching. During the war, because of the persecution of educated poles, Kuratowski went into hiding under an assumed name and taught at the clandestine Warsaw University. After the war he helped revive polish mathematics,serving as director of the polish National Mathematics Institute. He wrote over 180 papers and three widely used textbooks.