Nests are generally built deep inside tangles of epiphytic bromeliads in trees.

Eggs are laid in clutches of two and may be either pale blue with some very dark purple spots or white with evenly spread-out small brown splotches.

As of 2024[update], it is classified as being least concern on the IUCN Red List, an upgrade from its previous assessment of near threatened.

The azure-shouldered tanager was originally described in 1817 as Saltator cyanopterus by the French zoologist Louis Pierre Vieillot on the basis of a specimen from Nova Friburgo, Rio de Janeiro.

The throat and underparts are paler than the upper body, while the rump, uppertail coverts, and tail are bright blue.

The upperwing-coverts are a rich, glossy violet-blue and the greater coverts are dark with wide turquoise-blue edges.

It has been reported as far west as Paraguay, but these records are thought to represent misidentified sayaca tanagers.

[8] Breeding has been observed in October in Espírito Santo and in September in Rio de Janeiro.

Nests are generally built in tangles of epiphytic bromeliads in trees 10 to 12 m (33 to 39 ft) tall.

[8][13] They are 4.13–6 m (13.5–19.7 ft) above the ground and are located deep inside the tangles, where nests are sheltered from light and rain.

[8] Nests are shallow bottom-supported cups and are made mainly of long strips from dry bromeliad or other leaves.

The first recorded descriptions of eggs mention them as being pale blue with some very dark purple spots; however, modern descriptions have found eggs to be roughly elliptical in shape, with a white background marked with evenly spread-out small brown splotches.

[8] Azure-shouldered tanagers are parasitized by the feather mite Amerodectes thraupicola and the cestode worm Anonchotaenia brasiliensis.

[6] Historically, the lowland forests this species inhabits were threatened by deforestation caused by agriculture, mining, and plantations.

[1] Azure-shouldered tanagers have been recorded as being traded illegally in Brazilian street markets in Rio de Janeiro.