The most distinctive features of Carnotaurus are the two thick horns above the eyes, and the extremely reduced forelimbs with four fingers. It had a small skull, a thick chest, and a thin tail. The eyes of the Carnotaurus faced forward, which is unusual in a dinosaur, and may indicate binocular vision and depth perception.
A single nearly complete skeleton has been described including impressions of skin along almost the entire right side, that show Carnotaurus lacked feathers, unlike many other theropods discovered recently (see also feathered dinosaurs). Instead, the skin is lined with rows of bumps, that become larger toward the spine.