Technical Abstract: Crop simulation models and model-based decision support systems are increasingly used to assist agricultural research and development. The systems approach and modelling tools have been linked down to scales of functional genomics and up to regional scales of natural resource management. Although crop simulation modelling emerged many years ago, the progress seems to have slowed in recent decades. An international symposium was held from 19 to 22 April 2008 in Nanjing, China, with the following two main goals: 1. To exchange the state-of-the art of current modelling and simulation approaches, as well as recent progress on crop simulation models and decision support tools, 2. To explore future directions needed for advancement and potential opportunities for team collaboration in crop simulation modelling. A special issue of NJAS – Wageningen Journal of Life Sciences reports selected highlights of the symposium. Papers report on the recent progresses in crop simulation modelling and the way they contribute to agricultural research and development. The subjects in these papers largely deal with modelling eco-physiological processes in crop plants, functional and structural plant modelling, and application of crop simulation modelling to decision support.