The fur of the Emperor Tamarin is predominantly grey colored, with yellowish speckles on its chest. The hands and feet are black and the tail is brown. Outstanding is its long, white mustache, which extends to both sides beyond the shoulders. The animal reaches a length of 24 to 26 cm (9½ to 10¼ in), plus a 35 cm (13¾ in) long tail. It weighs approximately 300 to 400 g (10½ to 14 oz).
It lives in the southwest Amazon Basin, in east Peru, north Bolivia and in the west Brazilian states of Acre and Amazonas.