The ChS3 (Russian: ЧС3) is a type of 4-axle passenger direct current (catenary voltage of 3 kV) electric locomotive, manufactured in 1961, which was used in the Soviet Union and the Russian Federation.

In 1960, due to the increase in passenger trains, the Skoda factory was ordered to design and produce a more powerful locomotive type than the ChS1.

The ChS3 started off serving the Moscow-Kharkov line, before being transferred to the Trans-Siberian Railway, where they operated until 1991.

A 1,435 mm (4 ft 8+1⁄2 in) standard gauge version was produced by Skoda for Czechoslovakia ČSD Class E 499.1 and Poland PKP class EP05.

The Polish PKP class ET40 Bo-Bo+Bo-Bo locomotive was also based on the design of the ChS3.