A mattress is a large rectangular pad used to support an inclined body and is designed to be used as a bed or as part of a bed on a bedstead. Mattresses can be made of a suture or similar boxes, usually heavy cloth, containing hair, straw, cotton, foam rubber, or metal spring frame. The mattress may also be filled with air or water.

The mattress is usually placed on the top of the bed frame, which can be solid, such as a platform bed, or elastic, such as a bed frame. With cork and wire box spring or plate strip foundation. Popular in Europe, a sofa combines the mattress and the bottom of the bed in a padded foot unit. Divans have at least one internal spring layer and buffer material. They may be equipped with an auxiliary mattress and / or removable "hat". Mattresses can also be filled with air or water, or various natural fibers, such as bedding. Kapok is a common mattress material in Southeast Asia, and also a coconut fiber in South Asia.

Conventional mattresses consist of two main parts - a core or "support layer" and an interior or "comfort layer" wrapped in a thick fabric called a tick.

The interior layer covers the mattress and provides cushioning and comfort. The interior layer consists of three parts: insulator, middle interior and quilt.

Mattresses are usually made to meet market-specific bed size standards.