Cockroaches and stink bugs are two of the most common uninvited insects in homes, but they differ in nearly every way that matters: body shape, behavior, health risks, and how you get rid of them. If you’ve spotted a bug and aren’t sure which one you’re dealing with, the differences are easy to spot once you know what to look for.
How to Tell Them Apart
The fastest way to distinguish these two insects is body shape. Stink bugs have a wide, flat, shield-shaped body with five distinct points, almost like a medieval coat of arms. Cockroaches are oval and elongated, with a sleek, low-profile body built for squeezing into tight spaces. Both are roughly similar in size (most common species of each run about half an inch to over an inch long), but their silhouettes are unmistakable once you compare them side by side.
Antennae offer another quick clue. Stink bugs have short, five-segmented antennae that look chunky and angular. Cockroaches have long, thin, thread-like antennae that can be as long as or longer than their bodies. If the antennae are whip-thin and sweeping, you’re looking at a cockroach.
Wing structure is different too. Stink bugs belong to the order Hemiptera, meaning “half wings.” Their front wings are partly leathery and partly membranous, with a distinctive triangular plate called a scutellum visible between the wings on their back. Cockroaches have fully membranous wings (when they have functional ones at all), folded flat against their backs. Many cockroach species rarely fly despite having wings, while stink bugs are clumsy but willing fliers.
Their mouthparts reveal entirely different lifestyles. Stink bugs have a needle-like, tube-shaped proboscis designed for piercing plant tissue and sucking out juices. Cockroaches have chewing mouthparts built for eating just about anything, from crumbs to paper to soap residue.
Why They Enter Your Home
Cockroaches and stink bugs come indoors for completely different reasons, and understanding the motivation tells you a lot about how serious the problem is.
Cockroaches are looking for food, water, and warmth. They’re year-round indoor pests that thrive in kitchens, bathrooms, and anywhere moisture collects. A cockroach infestation tends to grow over time because they actively breed indoors, sometimes producing hundreds of offspring from a single female. They’re nocturnal, so spotting one during the day often means the population is already significant.
Stink bugs enter homes for one reason: to survive winter. As days get shorter and temperatures drop in September and October, brown marmorated stink bugs (the species most likely to invade homes) seek cool, dry, protected spaces to hibernate. They congregate on sun-warmed exterior walls, then slip through cracks around windows, doors, and foundations. Once inside, they settle into unheated attics, wall voids, and garages. Critically, stink bugs do not breed or reproduce indoors. They overwinter in an unmated condition and leave in late spring to return to outdoor plants where they lay eggs. So a stink bug “infestation” is really a temporary boarding situation, not a growing colony.
Health Risks and Allergens
This is where the two insects diverge most sharply. Cockroaches pose real health concerns. Proteins found in their saliva, droppings, and shed body parts are potent allergens that trigger immune reactions in many people. Symptoms range from skin rashes and sneezing to coughing and chronic congestion. For people with asthma, cockroach allergens are a well-documented trigger for attacks. You’re at higher risk for cockroach allergy if you already have asthma, eczema, hay fever, or a family history of allergic conditions. Beyond allergies, cockroaches crawl through drains, garbage, and sewage before walking across kitchen surfaces, mechanically spreading bacteria wherever they go.
Stink bugs, by contrast, are essentially harmless to humans. They don’t bite, sting, or transmit disease. They don’t damage household structures. Their only real offense is the smell, which brings us to the next point.
The Smell Factor
Stink bugs earned their name honestly. When threatened, handled, or crushed, they release a chemical cocktail from glands on their abdomen. The secretion contains long-chain aldehydes and esters that produce a sharp, pungent odor often compared to cilantro, burnt rubber, or skunks. The smell is a defense mechanism meant to deter birds and other predators. It lingers on skin and fabrics but is not toxic.
Cockroaches produce their own distinctive musty, oily smell, especially in large numbers. The odor comes from pheromones they use to communicate and from their droppings accumulating in hidden spaces. While less dramatic than a stink bug’s defensive burst, the cockroach smell is a sign of a sustained infestation rather than a one-time event.
Seasonal Patterns
Cockroaches are active year-round indoors, though they may be more visible in summer when populations peak and outdoor species wander inside seeking water during hot, dry stretches. Species like the German cockroach live exclusively indoors in temperate climates and don’t have a true seasonal cycle.
Stink bugs follow a predictable annual rhythm. Adults feed on fruit, vegetables, and ornamental plants through summer, then begin migrating toward buildings on warm sunny days in September and October. They hibernate through winter, become sluggish but occasionally visible indoors on warm days when they’re roused from dormancy, then leave structures in late spring to reproduce outdoors. By midsummer, the cycle starts building again with a new generation of adults.
How to Get Rid of Each One
Stink Bugs
The most effective approach is physical removal and exclusion. Vacuum them up or pick them up by hand and deposit them outside. Be aware that crushing or vacuuming them can release their odor (though the smell will not attract more stink bugs into your home, despite the common fear). A simple DIY trap works well: fill a roasting pan with soapy water, place it in a dark room, and aim a desk lamp at the water’s surface. Stink bugs are attracted to light and will fly into the water.
Indoor pesticides are generally ineffective against stink bugs. If you want chemical treatment, correctly timed outdoor perimeter sprays applied before the fall migration can reduce the number entering your home. The real long-term fix is sealing entry points: caulk around windows, repair foundation cracks, install door sweeps, and screen attic vents. Since stink bugs don’t reproduce indoors, preventing entry in autumn solves most of the problem.
Cockroaches
Cockroach control requires a more aggressive, sustained strategy because they breed indoors and hide in places that are hard to reach. Start by eliminating food and water sources: fix leaky pipes, store food in sealed containers, clean grease from stovetops, and take out garbage regularly. Gel baits placed in cracks near kitchens and bathrooms are among the most effective treatments for home use, as cockroaches carry the bait back to harborage areas where it spreads through the colony.
Sealing entry points matters here too, especially gaps around pipes, electrical conduits, and baseboards. Sticky traps help monitor where cockroaches are most active so you can target treatments. For heavy infestations, professional pest control is often necessary because cockroaches reproduce quickly, develop resistance to certain chemicals, and nest deep within wall voids and appliances where consumer products can’t reach.
Damage to Property and Belongings
Cockroaches can stain surfaces with their droppings, damage book bindings and wallpaper by feeding on the glue, and leave an oily residue on items they contact repeatedly. In large numbers, their accumulated waste and shed skins degrade indoor air quality.
Stink bugs cause no structural or material damage inside homes. Outdoors, they’re agricultural pests that feed on fruit crops, soybeans, and ornamental plants, which is why they became a major concern after the brown marmorated stink bug arrived in the U.S. from East Asia in the late 1990s. But inside your house, they’re just waiting out the winter.