In manufacturing, a clean room is an enclosed area protected against dust that might interfere with the manufacturing process. Such rooms are commonly used in integrated circuit fabrication plants, where the products are so sensitive that a dust particle in the wrong place could cause significant damage.

The air entering a clean room from outside is filtered to exclude dust, and the air inside is constantly recirculated through more filters to remove internally generated dust. Staff enter and leave through air locks, and wear protective clothing such as hats, face masks, boots and cover_alls. Equipment inside the clean room is designed to create as little dust as possible. Materials such as paper and fabrics made from natural fibres are often excluded.

The air-conditioning in a clean room often causes the humidity to fall below normal levels, so extra precautions are necessary to prevent electrostatic discharges.

Clean room design is a different manufacturing technique and is discussed in a separate article.