This proceedings contains a selection of peer-reviewed papers presented at the IAG Scientific Assembly, Postdam, Germany, 1-6 September, 2013. The scientific sessions were focussed on the definition, implementation and scientific applications of reference frames; gravity field determination and applications; the observation and assessment of earth hazards. It presents a collection of the contributions on the applications of earth rotations dynamics, on observation systems and services as well as on imaging and positioning techniques and its applications.