Corn syrup's major uses in commercially prepared foods are as a thickener, a sweetener and as a humectant – an ingredient that retains moisture and thus maintains a food's freshness.

In the United States, cane sugar quotas raise the price of sugar; hence, domestically produced corn syrup and high-fructose corn syrup are less costly alternatives that are often used in American-made processed and mass-produced foods, candies, soft drinks and fruit drinks.

Glucose syrup was the primary corn sweetener in the United States prior to the expanded use of high fructose corn syrup production. HFCS is a variant in which other enzymes are used to convert some of the glucose into fructose. The resulting syrup is sweeter and more soluble. Corn syrup is also available as a retail product.

If mixed with sugar, water and cream of tartar corn syrup can be used to make sugar glass.