"Eodromaeus" was a relatively small dinosaur, with a total length of about from nose to tail, and a weight of about . The trunk was long and slender. It is unknown how fast "Eodromaeus" could run: about has been suggested. The animal was, like all early dinosaurs, bipedal. The forelimbs were much shorter than the hindlimbs, ending in hands with five digits. Digits IV and V were very reduced in size.