This book constitutes the thoroughly refereed post-conference proceedings of the Third IFIP TC 12 International Conference on Computer and Computing Technologies in Agriculture, CCTA 2009, held in Beijing, China, in October 2009. The 80 revised papers were carefully selected from numerous submissions. The papers cover a wide range of interesting theories and applications of information technology in agriculture, including simulation models and decision-support systems for agricultural production, agricultural product quality testing, traceability and e-commerce technology, the application of information and communication technology in agriculture and universal information service technology, and service systems development in rural areas.