The blue-billed curassow is black with white feathers on its rear underbelly and at the tip of its tail. It has a light-gray bill with fleshy blue cere.
Females are black with black-and-white crest feathers and fine white barring on their wings and tail. They have a ruddy lower belly and a bluish base to their bill. Only the female grows a knob on the bill.
The blue-billed curassow is a large bird, standing 32-36 inches (83-93 centimeters) tall. Males are usually larger than females.