AbstractBoth soft white wheat and yellow corn flours were reacted with ethylenimine by a continuous, dry process capable of making up to 300 pounds of cationic aminoethyl cereal flour per hour. When either cationic flour was evaluated as a wet‐end paper additive, each was equivalent to a high‐quality commercial cationic corn starch in improving dry‐strength properties of paper and increasing pigment retention. Laboratory storage of the flour products for 1/2 year did not change their effectiveness. Estimates based on a plant producing 15 million pounds of cationic flour a year indicate that the cost‐to‐make is about 10 cents per pound.