This is the last and current title of the famous institution where most of the brilliant early research was conducted which gave Britain its historical lead in protein crystallography and molecular biology. Under its original name of Unit for the Study of the Molecular Structure of Biological Systems it was set up in Cambridge by the Medical Research Council from 1 October 1947 with a staff of two, M.F. Perutz and J.C. Kendrew, housed in the old Cavendish Laboratory in Free School Lane. The Unit expanded rapidly - by 1950 F.H.C. Crick and H.E. Huxley were already working there and J.D. Watson arrived in Michaelmas 1951 - and was renamed the Molecular Biology Research Unit in 1956. Although plans were put forward by Perutz, and accepted by the MRC, in 1958 for its expansion into a Laboratory of Molecular Biology with its own building, the work continued at the Cavendish in increasingly cramped conditions until 1962, when new quarters were opened by the Queen in the University Postgraduate Medical School on the New Addenbrooke's Hospital site. A further major extension was agreed in 1964.

M.F. Perutz was Chairman of the Laboratory until he reached retirement age in 1979, his successors being S. Brenner (until 1986) and A. Klug. Kendrew was Deputy Chairman and Director of the Division of Structural Studies until 1974 when he was seconded to EMBL.

The fortieth anniversary of the first MRC Unit was marked in 1987 by various celebrations, gatherings, articles and TV programmes; information about some of these is at MS. Eng. c. 2415, Folder D.39.