Sahachirō Hata (秦 佐八郎, Hata Sahachirō, March 23, 1873 – November 22, 1938) was a prominent Japanese bacteriologist who researched the bubonic plague under Kitasato Shibasaburō and assisted in developing the Arsphenamine drug in 1909 in the laboratory of Paul Ehrlich. Hata received three unsuccessful nominations for the Nobel Prize, one from Swiss surgeon Emil Kocher for Chemistry in 1911 and two by Japanese colleagues Hayazo Ito and G Osawa for Physiology or Medicine in 1912 and 1913, respectively.