Medicine: Biographies
- Ignaz Philipp Semmelweis
- Ivan Petrovich Pavlov
- Jack Kevorkian
- Jacob Henle
- Jacques Monod
- James Carroll
- James Lind
- James Watson
- Jan Ingenhousz
- Jean Cruveilhier
- Jean Martin Charcot
- Johannes Fibiger
- Johannes Peter Muller
- Johannes Von Muralt
- John Franklin Enders
- John Graunt
- John Hunter
- John Jacob Abel
- John James Rickard Macleod
- John Morgan