ABSTRACT: Cheddar whey powders from the West Coast, Midwest, and East Coast regions of the United States were analyzed for composition, microbial content, solubility, wettability, hygroscopicity, color, and sensory quality. Seasonal variations were investigated by sampling during both winter and summer. Each sample was analyzed after 3- and 9-mo storage in the original packaging in a controlled environment (21°C, 30% relative humidity). Compositional parameters were within specifications except for calcium content, which was low. The largest variability among processors was observed in free moisture (1.1% to 2.8%) and salt content (2.18% to 4.22%). The microbial content was mostly low although 1 sample had a standard plate count >50000 colony-forming units (CFU)/g, and some variability was observed in the content of spore formers. Large variations were observed in solubility index (from <0.1 to 4.0 mL) and in wettability (from 5 to >300 s). Titratable acidity ranged from 0.098% to 0.295% lactic acid and pH from 5.27 to 6.44. The powders ranged from slightly to extremely hygroscopic. Cooked flavor and aroma were the most intense attributes for all the whey powders. There was suggestive evidence of differences between the winter and summer production in regard to the cooked flavor and aroma, oxidized flavor and aroma, barney aroma, sour and salty taste. This study demonstrates that there are significant differences among commercial whey powders that could impact the application in further processing.