Sysmex Corporation (シスメックス株式会社, Shisumekkusu Kabushiki-gaisha) is a Japanese company headquartered in Kobe that is engaged in the health care business. Originally called TOA Medical Electronics (a branch of the TOA Corporation), the Sysmex brand was established in 1978, and were mainly involved with haematology analysers. The company was renamed Sysmex Corporation in 1998 taking advantage of brand recognition of their machines.

In addition, through its associated company, Sysmex is also engaged in the sale of extracorporeal diagnostic agents, as well as the import and sale of medical devices. The company distributes its products in the domestic market and to the overseas markets including the United States, Germany, the United Kingdom, China and Singapore, among others. It has offices and factories throughout Asia, as well as branches in Europe, Canada, United States, Australia and New Zealand. As of March 31, 2022, Sysmex had 76 subsidiaries and one associated company in total. On April 1, 2011, Katakura Industries Co., Ltd. sold its biological science research department to the company.^{[citation needed]}