Connectivity is a quantitative indicator of landscape structure, and connectivity of urban green areas is an indicator of ecological integrity in urban landscapes. The purposes of this study are to assess the connectivity of urban green areas in Seoul, and to develop a method of siting new green areas for better connectivity. Diverse methods for connectivity assessment and indices of connectivity are reviewed and applied to the connectivity assesment of green areas in Seoul. The indices of connectivity of green areas in Seoul turned out to be higher than expected, maybe because many of them are rather evenly distributed, serving as stepping stones, and because there are many riparian corridors, including the Han River. Analysis also shows the optimum location of new green space patches or corridors will be those spots that would link the mainland, or large green areas outside the city, and existing green areas in the city. Restoration of urban streams as ecological corridors will significantly enhance connectivity. Three different scenarios with increasing numbers of new green areas in the city were then prepared. The changes of connectivity were measured and the possible success rates of animal dispersal were simulated. The results revealed that restoration of streams will increase the connectivity and success rates of animal dispersal.