In this paper, we describe the contents and methods of “Korea Patent DataProject (KoPDP)”. The project collects all utility patents granted from the KoreaIntellectual Property Office (KIPO) for the period 1948-2016 and the US Patentand Trademark Office (USPTO) for the period 1976-2017. The project alsomatches their assignees to firms in DataGuide 5.0, a Korean financial database.The resulting dataset includes total 14,803 listed and non-listed Korean firmsmatched with their Korean and US patents, in addition to a host of accountingand financial information. Over 45% of all sample KIPO patents and 87% of USpatents assigned to Korean assignees are matched. We explain the detail of ourmatching procedures and also provide a coherent industry classification systemfor both sets of patents.