This Congress was originally planned to be held in Moscow, Aug 1937, and Darlington was invited by the Exhibition Committee to take responsibility for the section 'Chromosome structure and the mechanism of meiosis'. It proved impracticable to hold the Congress in Moscow in 1937 but the Russian government gave permission for the Congress to be held there in 1938. The question of the location of the Congress was reconsidered by the International Committee of Genetics Congresses and Edinburgh decided upon. Russian scientists were unable to attend the Congress in Edinburgh.

Material comprises correspondence re the postponement of the Congress.