Daiichi Sankyo didirikan pada tahun 2005 melalui penggabungan Perusahaan{{nihongo|Sankyo SankyoCompany, Limited (|三共株式会社, |Sankyō Kabushiki Kaisha )}} dan {{nihongo|Daiichi Pharmaceutical Company, Limited (|第一製薬株式会社, |Daiichi Seiyaku Kabushiki Kaisha ) }}, yang merupakan [[perusahaan farmasi]] berusia seabad yang berbasis di [[Jepang]]. Sankyo Co., Ltd. didirikan oleh Dr. [[Jokichi Takamine]], yang mematenkan isolasi adrenalin.<ref>{{cite [3]web|last1=Bennett|first1=Joan|title=The [4]Time Line: Adrenalin and cherry trees|url=http://pubs.acs.org/subscribe/archive/mdd/v04/i12/html/12timeline.html|website=pubs.acs.org|accessdate=24 January 2016}}</ref><ref>{{cite book|last1=Kawakami|first1=K. K.|title=Jokichi Takamine: A Record of his American Achievements|date=1928|publisher=William Edwin Rudge|location=New York}}</ref> Takamine juga merupakan presiden pertama Sankyo Co., Ltd dari Maret 1913 - Juli 1922.<ref>{{cite [5]web|title=13th Takamine Memorial Daiichi Sankyo Prize Winner Announced - Media & Investors - Daiichi Sankyo|url=http://www.daiichisankyo.com/media_investors/media_relations/press_releases/detail/006324.html|website=www.daiichisankyo.com|accessdate=24 January 2016}}</ref>
