Concept maps are used to assess student and cohort learning of sustainable development. The concept maps of 732 first-year engineering students were individually analyzed to detect patterns of learning and areas that were not well understood. Students were given 20 minutes each to prepare a concept map of at least 20 concepts using paper and pen. The maps were then analyzed using three different methods. The first method considers only the structure of the map by quantifying its features. The second method considers the content and comprehensiveness of the map by classifying every concept included using a new taxonomy. The third method scores the maps against a rubric that considers the correctness of the maps' propositions as well as the maps' comprehensiveness and complexity. The results show that concept maps are a useful tool in assessing the knowledge and understanding of sustainable development concepts and that the students surveyed have a good awareness about the technical, social and environmental aspects of the domain. They did not include many concepts relating to equity and economic impact of sustainable development policies.