Crested Serpent-Eagle is rather a medium-sized raptor, often seen soaring above forests.
Adult male has brown plumage. Upperparts are dark brown, with several fine white spots, mainly on wings and scapulars. Wings are relatively short and broad.
Underparts are slightly paler, almost pale reddish-brown. Breast is finely barred with dark brown. Rest of underparts is spotted with white. Underwing coverts are pale brown. Tail and underside of flight feathers are black, with broad white band.
Head is dark brown, with thick crest on nape. This crest is brown, finely barred with white. Hooked, strong bill is black with yellow cere. Eyes are yellow. Legs and feet are yellow.
Both sexes are similar.
Juvenile has whitish head, underparts and underwing.
We find numerous subspecies which differ in size and colour.