Which? Don't Buy cot mattresses

Don't put your baby's sleep at risk or waste your money on a terrible cot mattress.  

A Don't Buy mattress won't stand up to night after night of wriggly sleep, baby sick and nappy leaks. Or, it will fail to give your baby the vital support he or she needs in those early days and as they grow. 

Our tough lab tests uncover those mattresses which may let you down and highlight the cot mattresses you should avoid.

Join Which? to find out which cot mattresses we've named as Don't Buys.

What makes a Don't Buy cot mattress?

We've seen cot mattresses where the springs don't go right to the edge, where waterproofing only covers part of it (so little leaks could turn into a big cleaning job in the middle of the night) and even those that could be a smothering risk (see below). 

A good mattress will be firm to aid safe sleep and stays firm as your baby grows. It will also stay dry whatever your baby does to it. 

Confused about what to look for when buying a cot mattress? See our guide on how to buy the best cot mattress.

How we uncover the best and worst cot mattresses

Which? has reviewed the latest cot mattresses from all the big brands including Ikea, Cuggl, Mamas & Papas, John Lewis and Silentnight

Our in-depth testing means we can recommend those cot mattresses that are firm, breathable and will help to keep your little one cool. Plus those that last through tough durability tests, and support your baby as he or she grows. 

• Body support Your baby grows a lot in the first few years of his or her life, so it's crucial that the mattress you buy provides support for your little one's body as a baby and as a toddler. We use dummies of different weights, simulating children of different ages, to show how well each mattress supports children, from newborn to the age of five.
• Durability A firm mattress is a must with a newborn, and how well it will last is something you can't tell in a shop just by looking. Our tough tests simulate two to three years of use on every cot mattress to see how each one holds up to wear and tear.
• Staying clean and dry A cot mattress with a cover that's easy to whip off in the dead of the night when little (or big) accidents occur, and still looks as good as new after many spins in the washing machine is worth looking out for. We assess for fiddly to remove mattress covers that are going to shrink over time and fabric that will end up bobbling, and take points off for any which could give you sleepless nights.

Go to our how we test cot mattresses guide for more information about our rigorous cot mattress tests.

 Cot mattress reviews you can trust

A cot mattress is a pretty important purchase. Get the right one and your baby will sleep like – a baby. Which? is the only UK review site that tests cot mattresses to British Standards. 

Our extensive lab tests uncover mattresses that should be up to the job of providing your little one with a safe sleeping space, but aren't. 

Plus, we're independent, so you can be sure that our product recommendations are influenced only by our test results.

Which? is independent – we work for you, the consumer, so you can be sure that our product recommendations are influenced only by our test results. We're not influenced by third parties and we don't accept freebies from product manufacturers or retailers. We buy all the products that we test ourselves, so our advice helps you to make the right choice first time and avoid costly mistakes.

Not yet a Which? member? Join Which? to find out which cot mattresses we've named as Don't Buys. You'll also receive access to all of our exclusive online content - including all our reviews.