Taiwan and South Korea have the same constitutional system, approximate economic scale, and similar cultural backgrounds, yet they differ in degree of corruption. What political structures and legislative processes cause this outcome is the major question posed in this paper. The political structure in South Korea is a centralization-of-power model, while that in Taiwan is a separation-of-powers model. This paper proposes that Taiwan and South Korea have different types of corruption and different political structures, and the legislative process in South Korea is more compromising than that in Taiwan. These factors contribute to greater corruption in South Korea than in Taiwan. This study clarifies how particular institutional dynamics reduce or enhance the prospects for democratic governance and help to better understand how political structure and legislative process channel different types of corruption into different degrees of corruption. Studies on the relationship between constitutional structure and corruption have concluded that parliamentarism can help reduce corruption more than presidentialism. This thesis argues that a country with centralized power tends to be less corrupt than a country with separation of powers. If this argument and the rationale behind it hold true for countries with both parliamentary and presidential systems, we can expect that semi-presidential countries with a centralized system are less corrupt than those with a decentralized system, all else being equal. However, by comparing these two semi-presidential countries, we find that South Korea, with its centralized model, was more corrupt than Taiwan, with its decentralized model. This comparative case study provides a counterargument to the conventional wisdom of constitutional structure and governance.Taiwan and South Korea became democracies as part of the third wave of democratic transition. In their political development we find that the two countries have been similar in many respects. First, Confucianism has played an important role in the cultural and social life in both countries. Second, since the 1980s Taiwan and South Korea have experienced burgeoning economic growth as a result of exportCrime Law Soc Change (2009) 52:365-383