Although closely related to the American cockroach, the smokybrown cockroach is readily distinguishable by its uniformly dark brown–mahogany coloration. The smokybrown cockroach's thorax is dark and shiny.
They are found outside in wooded areas that provide shade and moisture. They can also be seen in protected areas around homes (tree holes and mulch) and in buildings and attics. Stacks of lumber and firewood, sewer-access openings and trash piles can contribute to infestations. Once in structures they are commonly found in attics or near fireplaces.
Cockroaches have been reported to spread at least 33 kinds of bacteria, six kinds of parasitic worms and at least seven other kinds of human pathogens. Medical studies have shown that cockroach allergens cause allergic reactions in children and can exacerbate asthma attacks.