In January 1939 the Institution and George Washington University were joint hosts for the Fifth Washington Conference on Theoretical Physics. These meetings had come about through the desire of the DTM group to draw on the best guidance possible and the need for George Gamow, Professor of Physics at George Washington, to circumvent the isolation from other theorists that resulted from his coming to Washington. Gamow had fled the Soviet Union with his wife and taken temporary residence in Niels Bohr's institute in Copenhagen, and Tuve had recommended him for the faculty position, hoping to profit from the mind that had explained alpha-particle radioactivity. The conferences were a condition of his employment. Later Edward Teller joined Gamow at George Washington.

The conference proved very popular with the leading theorists of the time because of the relaxed way in which the sessions were conducted, no formal papers or abstracts being required and, of course, no published proceedings. The subject for the first conference was problems in nuclear physics and was an acknowledged success. The fourth had probed the problem of stellar energy and was distinguished because Hans Bethe had worked out the first of the two major chains of nuclear reactions that drive the Sun while on the train back to Cornell.

The 1939 conference had as its topic low-temperature physics, but had nevertheless drawn theorists with interests in nuclear physics, fragmentation not yet having exerted the strong hold it now has.