This paper documents that a significant portion of trade for Taiwan and Korea follows the trend of world trade in moving toward a pattern of vertical specialization (VS). Noteworthy is the manufacturing sector, whose VS shares of exports has been steadily increasing and has accounted for more than 90% of the total VS shares of manufactured exports. For Taiwan, nearly 57% of the growth in exports is contributed by the growth in VS-based trade; for Korea, it is as high as 64%. In the analysis, we compare VS shares of exports with or without input-output circulation among domestic industries in an open economy. Using Taiwan as a case study, we further discuss the implications of trade liberalization through tariff reductions for trade verticality. Copyright Springer Science + Business Media, LLC 2006vertical specialization, fragmentation, tariff reductions,