Summary and ConclusionAn investigation has been made of the hygroscopic equilibrium of cottonseed over a range of 31% to 93% relative humidity. From 31% to 71% relative humidity the moisture content of cottonseed increased linearly from 6.03% to 10.27%. From 71% to 93% relative humidity the moisture content increased rapidly from 10.27% to 22.19%. When cottonseed was separated into meats and hulls, including linters, it was found that the hulls contained more moisture than the meats.On the basis of these results it is apparent that, when stored cottonseed is aerated, consideration should be given to the effect of local atmospheric conditions. The relative humidity of the air used for aeration can affect the moisture content of the stored seed either favorably or adversely. Although it may temporarily reduce heating by conduction of the heat of respiration, it may increase the moisture content and thus stimulate further respiration and heating.