Ernst von Fleischl-Marxow, also Ernst Fleischl von Marxow (5 August 1846, Vienna – 22 October 1891, Vienna), son of Karl Fleischl Edlem von Marxow and his wife Ida (née Marx) was an Austrian physiologist and physician who became known for his important investigations on the electrical activity of nerves and the brain. He was also a creative inventor of new devices which were widely adopted in clinical medicine and physiological research.