Anaxyrus americanus has a short, stout body, with a short broad head bearing large parotoid glands and having a broadly circular snout. The back is covered with different-sized warts and the venter is granular. There are three or four pairs of dark spots down the back, each accompanied by one large wart. Eyes are prominent. The arms and legs are tubular and warty. They are generally olive in color, with a brown crest (Wright and Wright 1949).
Males are roughly 54-85 mm in length. The back, sides and tympana are a dull citrine color with olive-citrine or yellow olive color on their hind legs and forelegs. The pectoral region is covered with scattered black spots, and these spots occur over the entire venter except for the throat and the center of the posterior venter. There is some apricot-yellow color across the arm insertion. The pupil is rimmed with citron yellow (Wright and Wright 1949).
Females are roughly 56-110 mm in length. The back is a light brownish or buffy olive. The bigger warts are on the back, and the warts are in the centers of buffy brown colored spots. There is a stripe down the middle of the back, of a deep-olive buff color, yellow, or vinaceous-fawn, that leads from parotoid to groin. In the center of the breast, there is a dark spot (Wright and Wright 1949).