Albertosaurus was a theropod, a member of the family Tyrannosaurids. The fossilized skeleton, field name “Pebbles”, was more than 55% complete with all areas of the skeleton being represented.

It was a bipedal animal, and like all tyrannosaurs was lizard-hipped. Its hind limbs were long and probably extremely powerful; each foot had three toes with large, sharp claws called tridactyl feet. Its front limbs, however, had only two fingers like the T. rex and were too short to reach its head; the function of its small arms is not known. The anatomical differences between the Albertosaurus and the T. rex are minimal and can probably be attributed to environmental stimulus and genetic isolation.