The MRC Mitochondrial Biology Unit (formerly the MRC Dunn Human Nutrition Unit) is a department of the School of Clinical Medicine at the University of Cambridge, funded through a strategic partnership between the Medical Research Council and the University.

The Unit was founded in 1927 using a donation from Sir William Dunn, who left £1 million to charity on his death in 1912.

Its original research focus was to investigate the role of vitamins in human health.

The Unit was restructured in 1998 under the directorship of Professor Sir John Walker to focus on mitochondrial research.

The Unit has three major scientific aims:[1] The MBU is organised into nine independent research groups[2] and includes 30-40 graduate students who are members of the University of Cambridge: Professor Judy Hirst FRS (2020 - ) [3] Professor Massimo Zeviani (2013 - 2019) Professor Sir John Walker FRS (1998 - 2013)[4][5] Dr Roger Whitehead (1973 – 1998) Dr Egon Kodicek CBE FRS (1963 - 1973) Dr Leslie Harris (1929 - 1963) Sir Frederick Gowland Hopkins (1927 - 1929)