American cockroach
A single female American cockroach can leave behind more than a hundred young during her roughly one-year adult life.
| Where | Basements, sewers and warm buildings |
|---|---|
| Size | 35 to 40 mm body length |
| When | January to December |
The American cockroach is the largest common cockroach found in and around buildings, reddish brown all over with a pale yellow band around the shield behind its head. Adults carry long wings that reach past the tip of the abdomen, though they rarely fly and instead rely on fast running to escape danger.
Females carry a purse-shaped egg case briefly before hiding it in a sheltered crack, and the nymphs that hatch need six months to a year to become adults. Indoors this cockroach can stay active year round, favoring warm, moist places such as basements, drains and sewers, while outdoor populations shelter in yards and foundation cracks during warm weather.
Traits
Habitat
Towns
Colour
Brown, Yellow
Active
Night
To people
Harmless to touch, but its shed skins and droppings can trigger allergies and asthma in some people.
Activity through the year
Often confused with
Similar reddish brown body, but has pale yellow margins running along the front edges of the wings as well as around the shield behind the head.
A uniform dark mahogany brown all over, lacking the pale yellow band around the shield behind the head that marks the American cockroach.
Questions
Is the American cockroach dangerous to people?
Harmless to touch, but its shed skins and droppings can trigger allergies and asthma in some people.
When can you see the American cockroach?
The American cockroach can be seen from January to December, at night.
Plate retouched from a photo by Vihansith Kulatunga, CC BY‑SA 4.0, iNaturalist Licence
The plate on this page is shared under the same licence as its source, CC BY-SA.
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Cockroaches and termites›Cockroaches›Periplaneta
Last updated 2026-09-27. Every entry is checked against published sources.