Abstract: From 1953 to 1954 a series of experiments has been carried out at Nanking on the vernalization of 59 varieties of rice collected from various parts of China. The results of these experiments may be summarised as follows: Different varieties, from early to late varieties, require different temperatures for the vernalization of rice. In general, all the varieties used gave favorable response to high temperatures (15--30℃). Among the 59 varieties, 8 of them require a temperature of 25--30℃, and 13 of them 15-20℃. For the majority of the varieties tested 12 days are usually sufficient; For the completion of vernalization, but 11 varietiesrequire more than 6 days and 10 varieties less than 6 days to complete this stage of development.