This is a tiny light brown moth with a wingspan of 1/2 to 5/8 inch. The wings narrow at the ends and are adorned with long fringe. Adults can fly, and when at rest these moths hold their wings parallel to the body. The mature larva is about 1/4 inch long and white with a darker head. Angoumois grain moths closely resemble other food and fabric pest moths.

The life cycle can vary from 1 to 6 months depending on temperature. About 40 eggs are laid on or close to grain. Eggs turn red before hatching into tiny larvae, which penetrate a single kernel of grain to feed and grow. Pupation occurs inside the kernel.

Larvae cause all the damage. This species has a preference for rice, whole oats, field corn, barley, rye, and other seeds. Moist grain is more attractive than very dry or old grain. They can be active at low temperatures and will infest grains in the field as well as storage. Low levels of contamination in large batches of grain may make the whole batch unmarketable.