A composition for enhancing the dewatering of a paper sheet on a paper machine and a method for using the composition is disclosed. The composition comprising one or more aldehyde-functionalized polymers comprising amino or amido groups wherein at least about 15 mole percent of the amino or amido groups are functionalized by reacting with one or more aldehydes and wherein the aldehyde functionalized polymers have a molecular weight of at least about 100,000. The method comprising adding the composition to the paper machine at a dosage of about 0.05 lb/ton to about 15 lb/ton, based on dry fiber.