I would just fold it in half widthwise, fold in the arms and then again in half lengthwise.

1) "RakuMon over on Rice Daddies had a post the other day called Folding a Onesie Requires an Engineering Degree. He has a really good point. How do you fold a onesie? Thinking back, I guess I just folded them like shirts and then in half again (I think, I was pretty drugged up at the beginning. They give you good painkillers after a c-section). What RakuMon was really wondering anyway was how you fold the kimonos and the pajamas with booties. If you are like me (and by like me I mean lazy and not picky at all) you just sort of fold them until they are smaller and then shove them in the appropriate drawer. What do you do if you are anal? I'm the wrong person to ask, so I am asking you guys. Here is another question. When the onesie comes with matching socks and a headband, or a hat, how do you keep it all straight? Great. I'm completely done having babies and I have given myself a headache thinking about baby laundry." Source: http://babble.com/CS/blogs/strollerderby/archive/2007/05/30/how-do-you-fold-baby-clothes-anyway.aspx 2) "When Kim gave them to me they looked pristine--not a wrinkle in sight! They were folded simply in half at the tummy and stacked on top of each other. I was amazed! That's what I do now--I fold them in half and stack them in Rachel's dresser. It makes them easy to riffle through, although I'm not sure that they look quite as elegant as Kim's folding job." "I tried so many different ways and I found that just folding them in half was the best." "I fold in the sleeves and then roll them up." "I would place them down face first on the floor, and then put a little book that I had that was tiny tiny, fold the sleeves over it, fold the snapped part up, and there you go! Just like using a magazine on a T-shirt! (that makes them all uniformed rectangles and they stack so much nicer. I'd like to thank the GAP for teaching me that...)" Source: http://motherslounge.blogspot.com/2007/12/how-i-fold-my-onesies.html 3) Also interesting: fold a T-shirt in two seconds: http://lifehacker.com/software/video-demonstration/fold-a-t+shirt-in-two-seconds-redux-331405.php