The wear of carbon steel in corrosive environments has been observed under the potential controlled conditions, and the mechanism of wear and friction in corrosive environments is discussed. In the wear of metals in corrosive environments, the fracture of adhesion points, the fracture by thermal fatigue, the rubbing off of corroded layer and the damage by corrosion fatigue are observed in accordance with the variety of corrosive agents, the corrosion intensity, the type of friction, the rubbing velocity and the contact load. In the oxidizing neutral media, the lubrication due to the corrosion products plays an important role in the behavior of wear, the minimum wear rate being obtained under the mild corrosiveness in the type of face contact. In the reducing acid media, the lubrication of corrosion products is not found because of their dissolution. In the corrosive wear of metals, the wear rate is much affected by the dissolution rate of metals because of the great effect of corrosion fatigue. The cathodic potential sufficient to protect the static corrosion is not adequate to the members under friction in corrosive environments, owing to the increase of the surface activity of metals. However, the protection from corrosion is not always expected to decrease the wear rate as is mentioned above.