What type of cheese is most commonly used in Tex-Mex chile con queso?

American cheese is the most commonly used cheese in Tex-Mex chile con queso.

Chile con queso, often shortened to queso, is a warm cheese dip flavored with chiles and other ingredients. Processed American cheese became popular for this preparation because it melts smoothly and remains creamy instead of separating easily. Restaurants may combine it with milk, cream, tomatoes, onions, jalapeños, or roasted green chiles.

The dish is related to Mexican queso fundido, but they are not identical. Queso fundido is typically based on melted natural cheese and is often served as a thicker, more dramatic preparation. Tex-Mex chile con queso is usually designed as a pourable dip for tortilla chips.

Some modern recipes use cheddar, Monterey Jack, or processed cheese products. Those variations do not change the traditional Tex-Mex association with smooth American cheese. The exact recipe differs widely between restaurants and regions.