A comparison was made of Coomassie Brilliant Blue R 250 and Amido Black 10 B for staining whey proteins separated by polyacrylamide disc electrophoresis. Acid whey was diluted with tris-glycine buffer and proteins were applied at a concentration of 0.2 mg. Following electrophoresis, gels were placed in a 20% solution of sulfosalicylic acid for 20 to 60 minutes to fix proteins, washed with distilled water, and stained in a 0.25% solution of Coomassie Brilliant Blue in distilled water. A staining time of 1.5 to 2 hr for Coomassie Brilliant Blue gave results comparable to staining by the Amido Black 10 B method. Major protein bands were visible within 30 minutes and more bands could be distinguished with longer staining. © 1969, American Dairy Science Association. All rights reserved.