As part of a study to understand the current status of Korean plant species propagated in foreign countries, we conducted extensive surveys on Korean living collections in the Arnold Arboretum of Harvard University, the oldest public arboretum in North America. Specifically, we collected and identified the voucher specimens of the living collections and further examined the collection databases to understand the history of how Korean plants were introduced to the Arboretum. We found that a total of 154 Korean taxa (belonging to 49 families and 81 genera) have been planted in the arboretum. Most plants originated from seeds that were directly collected in Korea or obtained via seed exchanges with botanical gardens in Asia, Europe, and U.S.A. Of the 154 taxa, 16 are Korean endemic species, and three are listed as endangered species. In addition, 62 taxa are as floristic regional indicator species of Korea used by the Ministry of Environment.