The massive bodies of Centrosaurus were borne by stocky limbs, although at up to 6 m (19.7 ft) they were not particularly large dinosaurs. Like other centrosaurines, Centrosaurus bore single large horns over their noses. These horns curved forwards or backwards depending on the specimen. Skull ornamentation was reduced as animals aged.
Centrosaurus is distinguished by having two large hornlets which hook forwards over the frill. A pair of small upwards directed horns is also found over the eyes. The frills of Centrosaurus were moderately long, with fairly large fenestrae and small hornlets along the outer edges.
Centrosaurus, which moved on all fours, had powerful front limbs that would have enhanced the animal’s speed and agility. A ball-and-socket joint in the neck would also have been useful in defense. it allowed Centrosaurus to turn its head swiftly and bring its sharp horn into play against large predators, such as Tyrannosaurus, that attacked from the rear.
The genus Centrosaurus gives its name to the Centrosaurinae subfamily. These were large North American horned dinosaurs characterized by their “prominent nasal horns, subordinate brow horns, short squamosals in a short frill, a tall, deep face relative to the chasmosaurines, and a projection into the rear of the nasal fenestra.” Its closest relatives appear to be Styracosaurus and Monoclonius. It so closely resembles the latter of these that some paleontologists have considered them to represent the same animal.