The Yellow Longbill uses its long, straight bill while foraging in forest undergrowth. It eats insects and some fruit, and the two described subspecies differ in plumage.
The nominate subspecies flavicans has a dark olive-gray crown, dark olive-green upperparts, and yellow-tinged back and rump feathers. Its bill is long and straight with a small hook. Subspecies hypochondriacus is paler above, with a whitish chin and throat and orange-tinged flanks.
It occurs in primary and secondary forest and in logged areas. It feeds mainly on insects, also taking some fruit, and forages in thick undergrowth and tangled creepers.
An extinction-risk assessment has not been added yet.