Recently, research community in Korea has shown a rapid growth in collaborating with Asian countries. In this study, we analyzed research collaboration among Asian countries using network analysis of co-authored papers as well as subject categories. The network of co-authored papers among Asian countries over the 5-year period since 2005 revealed that Japan, China, and Korea were positioned at the central part of the network and highly productive in collaborative research. In the analysis of the subject categories of co-authored papers in four different Asian regions with 2009 data, physics and material science were found the most productive subject fields in collaborative research in Northeast Asia. On the other hand, medical science was the most collaborative subject field in the remaining Asian regions.