UNESCO’s Science programmes are chiefly directed at fostering sustainable development and reducing the current imbalance between developing and developed countries in their respective access to research results. In this, UNESCO concentrates on international cooperations, on setting up international research networks, fostering capacity building at the individual and institutional levels, and adapting scientific policies to social needs. An interdisciplinary approach, dissemination of scientific insights to a broad public, and the monitoring of trends are among its key challenges. Particular attention is devoted to encouraging women in science.