This article examines the reasons “why Cross-Strait exchanges have expanded between the Republic of China(Taiwan) and the People’s Republic of China whereas similar developments have not occurred between the two Koreas.” There are three variables that are of special importance, interactions between the Taipei and Beijing compared with Seoul and Pyongyang, domestic political factors, and the role/attitude of United States. The growth of South Korean democracy dating back to 2000, and the development of a separate Taiwanese ‘identity’ are both significant political factors. In the international sphere, the United States is similarly important in both Cross-strait exchanges and inter-Korean relations, albeit its role has been markedly different in each case. First, the Chinese and Korean case there has been a general trend in the direction of increased exchanges. Second, domestically, both Taiwan and South Korea have begun to become post-ideological societies, with a far more practical and realistic attitude to their respective ‘rivals.’ Third, Domestic political conflicts that surround Cross-Strait policy in Taiwan and North-related policy in South Korea have been intensified as a result of changes in governments following elections. Fourth, while the United States remains a crucial partner of both South Korea and Taiwan, its influence in the region is less and less diminishing. On the other hand, the differences between the inter-Korean and the Cross-Strait are also numerous. First of all, security issues between the two Koreas have taken precedence over other competing political and economic issues. As Cross-Strait relations advanced as a result of non-political interactions between Taiwan and the mainland, the role of security or political concerns take a back seat. Another factor that has led to instability in North-South relations is a lack of institutionalization of those relations, the two Koreas do not recognize one another diplomatically, and therefore do not maintain formal or stable links. Such issues are added to by the fact that there are two competing and antagonistic methods of dealing with the issues related to North Korea in South Korean politics; the internationalist approach that seeks to build an international consensus to deal with North Korea, and the nationalist approach that seeks to deal with North Korean related issues through North-South dialogue. Similarly in Taiwan, there are two major approaches to dealing with the mainland, the first in the ‘One China’ approach – i.e. Chinese nationalism – the second is the ‘Taiwanese identity’ approach – i.e. Taiwanese nationalism, or separatism. International relations and the role of the United States also cannot be ignored. Whereas in inter-Korean relations, the United States continues to play an important role because of North Korea’s nuclear program, it has become a more peripheral player in Cross-Strait relations.