Cockroaches are living in my microwave. What do I do?
Replacing the microwave rarely helps, because the cockroaches live in the kitchen and the appliance is just a warm room. Unplug it, never spray inside, and bait around it instead.
Cockroaches love microwaves, printers, routers and coffee machines. These spots stay warm and dark, and in a kitchen there are crumbs close by. You do not need to take the appliance apart or keep buying new ones. You treat the room around it, and the ones inside come out to feed.
If you already replaced it and they moved into the new one, you did nothing wrong. It just tells you where they really live: in the kitchen, with the microwave as their favourite spot.
Why a new microwave did not fix it
Throwing out the infested item takes away the cockroaches inside it, and maybe some egg cases. It does not touch the ones behind the fridge, in the cupboard hinges or under the worktop. Put a new appliance in the same warm spot and they find it again.
The same goes for a printer someone gave you or a robot hoover from a market. The item may be how they got in. But once a few are loose, the problem is the room, not the object.
What is safe with electronics
- Unplug before you look. Then check the vents, the back panel and the gap underneath with a torch.
- Never spray inside. Insect spray in the vents can damage the electronics and leave residue next to your food. Aerosols near a hot appliance are a fire risk. And spraying pushes cockroaches deeper inside.
- Do not open a microwave casing. Parts inside can hold a dangerous electrical charge even when it is unplugged. Leave that to a repair technician.
- Wiping helps less than you think. Alcohol or a damp cloth only reaches what it touches, so it cleans the outside, not the cockroaches inside. Follow the maker’s cleaning advice and do not soak anything.
- Keep the inside clean. Wipe the turntable and walls after use. Food splashes are what keeps them interested.
Bait around the appliance, not in it
Two small indoor species like electronics: the German cockroach and the brown-banded cockroach. With both, bait does the work. They eat it, go back to their hiding place and spread it to the others.
- Find out which one you have. A German cockroach is small and tan, with two dark stripes behind the head, and sticks to kitchens and bathrooms. A brown-banded cockroach is about the same size, with pale bands across the body, and likes warm, higher spots all over the home, electronics in bedrooms included.
- Put small dots of gel bait close to the appliance. On the wall behind it, at the corners of the shelf it sits on, in the nearest cupboard hinges. Not in the vents and not on parts that get hot.
- Add an insect growth regulator if the label allows it in kitchens. It stops the young ones from growing into breeding adults.
- Leave the microwave where it is. Moving it around scatters them away from the bait.
- Put monitor traps on either side of it, plus under the sink and behind the fridge. Check them on the same day each week and write down the counts.
Gel bait and growth regulators are regulated products. Follow the label on where they go and how much to use, and check the product is allowed where you live.
Near food, kids and pets: keep bait off the surfaces where you prepare food, and keep it behind the cooker or fridge, where children and pets cannot get to it. If the label says not near food, it means it.
If it came in on something second-hand
Check second-hand electronics before they come into the kitchen. Do it outside, or in an empty bath on a light surface. Hoover the vents and seams, then look for droppings, which look like ground pepper or small dark smears. Our page on droppings and egg cases shows what to look for.
If one ran out of it, assume it may have had company. Keep the item away from food for a few weeks with a monitor trap beside it. Bagging and binning an infested robot hoover, washing your clothes and mopping were all reasonable steps. Whether they were enough is something the traps will tell you over the next few weeks.
When to get help
If you still catch cockroaches after a month of baiting, or you see them in daylight, call a professional. Tell them about the appliance so they treat around it. If you rent, tell your landlord in writing with dates and photos. Our page on how to record pests for a landlord shows what to send.
More questions
Is it safe to keep using the microwave?
If it works and the cooking space is clean, yes. Wipe it out, cover food, and replace it later once the kitchen is clear if you would rather.
Can I run it empty to cook them out?
No. Running a microwave empty can damage it, and the cockroaches sit in the casing, not the cooking space.
Will they move into my laptop or router?
They can use any warm device, especially near food. Keep the treatment focused on the kitchen and put a trap by any other device where you see one.
I wiped everything with alcohol before moving. Is that enough?
It cleans the surface only. Keep those items apart with a trap nearby for a few weeks and see what it catches.
If a product label ever says something different from this page, follow the label. Safety and labels