SummaryProcessing of cottonseed by the hydraulic press method has been carried out at two mills, one located about 100 miles farther south than the other. The varieties of seed processed and conditions during processing, which included cooking of moistened seed, were essentially the same at both mills. Seed was also processed at the more southerly mill by the screw press method for which seed was cooked without added moisture.The crude hydraulic‐ and screw‐pressed oils produced at the two mills were stored at different temperatures for a total of ten months, and samples of the oils were periodically refined and bleached. Seed was also stored at the two mills, and was periodically processed for comparison of the oils produced from stored seed with the stored oils. The absorption spectra of the crude, refined, and bleached oils were determined.The rate of increase of bleach color in the oils during storage of the seed and crude oils has been correlated with temperature of storage and changes in the absorption spectra of the oils.