Zein has been commercially isolated from corn gluten meal (CGM) by using a hot isopropyl alcohol base solution extraction and then chilling the extract to separate the zein from solvent. But high variation in the yield and quality has plagued processors. Although there have been numerous studies on the technology of zein extraction, studies investigating how CGM quality affects zein extraction yield and quality have not been published. In this study, CGMs, produced from two maize hybrids and subjected to five drying treatments, were used to determine the effect of these variables on zein extraction. The results showed that zein extraction yields, protein recoveries, and purities were higher in CGM from the maize hybrid with the higher protein content. CGM drying temperature and method were the other major factors in determining yield and purity of zein extracted from the meal. The yield and protein recovery of zein decreased as the drying temperature increased. Protein aggregation at high temperature is believed to be the primary reason for the lower yield. Zein yield, protein recovery, and purity were significantly lower in the CGMs subjected to freeze- and spray-drying than in the oven-dried CGM. A relatively higher pH value in the CGM slurries, more a-zeins with less polarity, and more a-zeins with pH 7.3 were characteristics of freeze- and spray-dried CGMs. Possible changes in protein during drying are deamidation, oxidation of sulfhydral groups on protein, and some hydrophobic bond formation which could interfere with zein extraction yield.