Sir Bernard Katz (1911 –2003) was a German-born Nobel Prize winning physiologist. Katz was born to a Jewish family in Leipzig. After studying medicine at the University of Leipzig, he fled to England in 1935 to escape Nazi persecution. He went on to work at University College London (UCL) under AV Hill, and on finishing his PhD in 1938, won the Carnegie Fellowship to study with John Eccles at the Kanematsu Memorial Institute in Sydney. After being naturalised in 1941, Katz served in the Royal Australian Air Force for the duration of World War II. In 1946, he returned to UCL and continued his research on the synapse. Katz became a Fellow of the Royal Society in 1952, the same year in which he became Head of the newly designated Biophysics Department at UCL. He was knighted in 1969, shortly before receiving the Nobel Prize for Physiology or Medicine in 1970 (with Julius Axelrod and Ulf von Euler), for his discovery that neurotransmitter release at synapses is ‘quantal’, meaning that the amount of neurotransmitter release is never less than a fixed minimum and, if more, this is an integer multiple of this amount. This functional evidence was later complemented by ultrastructural evidence of transmitter-containing, membrane-bound vesicles common to nerve endings and secretory cells. Katz became Emeritus Professor at UCL in 1978. On 20 April 2003, Sir Bernard Katz died aged 92. In 1999 The Physiological Society established the Hodgkin-Huxley-Katz Prize Lecture; this prestigious biennial lecture celebrates the contributions to the physiological sciences of Alan Hodgkin, Andrew Huxley and Bernard Katz.