Crocidura leucodon is dark grey-brown or chestnut-brown on its back, and white or grey on its underside. A sharply defined line separates the two colors on the sides, contributing to the common name "bicoloured white toothed shrew." The body is 68 to 87 mm in length, and the tail is 29 to 46 mm. Bicoloured shrews have a mass ranging between 6 and 13 g. The tail is covered with long, protruding hairs at right angles.

Bicoloured shrews have interesting dentition. Their teeth are white, because they lack pigment. In addition, these shrews have three unicuspid teeth in the upper jaw. The dental formula is 3/1 1/0 1/2 3/3 = 28 teeth.

The skull of Crocidura leucodon is differentiated from that of greater white-toothed shrews by a rostrum that is shorter and deeper, and unicuspid teeth that are more crowded.