Inserts included. Packaging may not or may not be included with this offer. This product is final sale and only available while supplies last. May not be returned. Not valid for store credit, refund, or exchanges. Color and/or closure may be substituted by Cotton Babies based on inventory availability.

bumGenius 4.0

{ one-size, pocket-style cloth diaper }

Best selling, top-rated, and recognized for its quality and performance. bumGenius 4.0 is a one-size, pocket-style diaper that will keep your baby dry and comfortable.

Look for our unique butterfly closure system to ensure that you are getting genuine Cotton Babies™ brand cloth diapers

Oeko‐Tex Standard 100 certification indicates that bumGenius diapers have been stringently tested and are free from harmful or problematic substances.

  • Stay‐dry lining is super soft and wicks moisture away from delicate skin
  • Waterproof outer cover and insert stopper prevents leaks
  • Accessible, replaceable, gentle elastic
  • Durable plastic snaps
  • 3x3 snap down design adjusts the sizing to fit small, medium and large sizes (approximately 8‐35+ pounds)
  • Trim, snug and comfortable stretchy tabs provide a custom fit
  • Pocket accommodates inserts for customized absorbency
  • Diapers are bundled with two inserts: a newborn insert and a one‐size insert for your older baby
  • Newborn insert works as an overnight booster for older babies or as extra absorbency for heavy wetters

Cloth diapering has never been so easy!

bumGenius One‐Size Cloth Diapers feature our patented butterfly closure system to provide a comfortable, trim fit. This simple design makes cloth diapering as easy as using disposables. The familiar design makes bumGenius one‐size cloth diapers perfect for care providers who might be resistant to cloth diapering (including daycares).

Buy Diapers Once

bumGenius One‐Size Cloth Diapers fit most babies from 8 to 35+ pounds. No sorting by size or having to carry multiple diapers when going out. Three snap‐downs on the front of the diaper allow you to easily adjust the size of the diaper as your baby grows. For newborns, fold down the insert stopper for an extra‐small rise.

Only the Best for Your Baby

The soft, waterproof outer fabric keeps the diaper trim on your newborn and toddler. Soft, sueded inner fabric gently wicks moisture away from your baby's skin. Super stretchy, gentle leg and back elastic with rolled out casings keeps in the yuk and help to keep red marks away. Our unique covered slot opening keeps your baby protected from moisture.


I love BumGenius 4.0 pocket diapers! I used fuzzibunz with my 1st and I absolutely despised them. Poor quality, leaked, and were not good quality. I was so frustrated that I finally gave up. Now, with my 2nd (5months old now) I decided to try BumGenius and I'm so glad I did. Great price! Great quality! Amazing product all around! I have had ZERO issues with these! Never had leaking issues or smells or anything. They are super easy to use and easy to wash. I would highly recommend BumGenius! And Cotton Babies is amazing too. Easy ordering and fast shipping. I ordered the snaps. BumGenius is golden. Will never go back to fuzzibunz or any other brand. :)


I would say that I'm overall satisfied with my 12-pack of diapers, they do the job and are the trimmest ones I've seen. However, if you're looking for a diaper to last through more than one child or a high quality diaper, this isn't it. My biggest problem is the "stay dry" micro-fleece liner and the flap to stuff the diapers in. The liner is a very flimsy fleece that doesn't wick moisture away very well. I've also had issues with the material just not getting clean compared to my other diapers (even after following instructions). The flap, on the other hand, needs to be pulled down well or else leaking around the waistband can occur too. In the future, I'd like to see BumGenius use better materials, especially considering that people pay a fair amount of their hard earned money to buy them!


I love these diapers! I ruined my first stash bc I washed them on a sanitize cycle regularly which makes the water hotter than normal and it definitely cut the life if my elastic and pul. But that's to be expected. I purchased some charlie bananas as well and notices that just by washing in hot water the pul is sticky and they get moist, not leak just feel moist when baby is wet. I actually purchased 6 4.0's from the seconds sale and so far I absolutely love them! I don't wash any ofy covers in hot water anymore though, just warm. I'm hoping that this will prolong the life of the elastic and the pul. Even if I have to buy a new set for my neXT baby after using this stash for 2 or more years I still save thousands of dollars! I recommend these to everybody I know that is thinking of cloth diapering or already cloth diapering. Love love love!!


I wrote an honest review of this diaper on this page before, but the cottonbabies people very quickly removed it. I used to absolutely love these diapers, until recently. They were my favorite diapers in our stash and we have at least 30 of them. We also supplement with prefolds and few other brands of pocket diapers, but these are the dominant diaper in our stash. I used them on our first child for about 2 years and our second child has been in them for almost 2 years (not yet potty trained). Shortly after our second child was born, I realized all the elastics were stretched out, so I replaced them all in the hopes that that would prolong the life of our diapers and it did, thankfully! (I consider that normal maintenance for cloth diapers which I expected to need to do at some point.) However, in the last 6 months or more I have begun to notice parts of the PUL are actually cracking and developing holes. In most diapers, this is occuring in the strip of PUL at the top inside margin of the diaper that touches the babys belly. On a side note, I have only ever washed my diapers according to manufacturer instructions, with cloth-safe detergent, and I do not put them in the dryer ever. So I was very disappointed to see this happening, and when I contacted the customer service to ask if they have seen this before, and if they really expect their diapers to not last through 2 children, her response was that is considered normal wear and tear. Im sorry, but I completely disagree. This is a quality issue, the PUL is literally falling apart which is now affecting the function of the diapers. And this has begun to happen in at least 8 of my diapers. When I spent the $$$ up front with my first child to cloth diaper instead of using disposables, I had hoped to be able to use them for all my children, but they are not even going to last through my second child. This is EXTREMELY disappointing, and even more disappointing is the way the customer service has handled the issue. I really want to be able to recommend these diapers to my friends when they talk to me about cloth diapering, but I dont feel that I can do that anymore. Looking at the possibility of needing to re-purchase my entire stash in the next few months, this makes me seriously regret choosing this product.


I have to admit. I was scared to try the BY 4.0's because of their bad reviews about their elastic. But one day I finally decided to try out a few. I own so many cloth diapers from many different brands and I have some I hate and some I love. But once I tried out the B'S 4.0 dipes. I was totally in love. These are now my favorite go to dipes everyday. I had to get more and my stash is budding up more of 4.0's. We love them. We have never had leaks or any sort of problem with these. And we have a heavy wetter. Sleeps through the night with both inserts. Love them. My mom baby sits my kids and she never complains when she uses these on my baby. I definitely recommend them. They are much better than the freetimes. I like the idea of the free times but those leak on us every single time. Even my mom hates them.

Read all 220 reviews