This is a challenge but can be done. I put stabilizer in the hoop cut away. Then I sprayed the stabilizer and opened up the onesie laying the front down on the stabilizer and pushing the rest of the onsie on the sides. I then used wash away stabilizer and basted that in place and then stitched ou the design So when you put the onesie down it will look like you have a wall around the area to be stitched. After you do the first one it will get easier. This is what I do. I am not sure what anyone else does.
Cindy B

Lynn, I do it about the same way as Cindy stated - so I will leave a *4U.

First I spray my stabilizer and place on the inside of the front of the shirt. Next I hoop the front not streching the fabric. Tighten the hoop and then I roll the back of the onesie until it is at the edge of the hoop. Then I use hair clips like banana clip but straight and I clip the back fabric so it won't get under the hoop. Good luck hope this helps.

I do it like cindy but no spray I baste roll it out of the way & hold with hair clips. works everytime *

Keep in mind you can only embroider a small design.

And remember to iron on the soft backing when you're done so baby skin doesn't get irritated by stitching on underside. And be sure to mark your centerline so design is straight. It's so tiny that sometimes your center gets "lost".

Thank you everyone for your help. It worked perfectly. It would be easier on a larger size.
:o)

Embroidery Library has a step by step tutorial on embroidering baby garments including onesies.

OMG! What is elastic lace? You sew it on the "bottom" on the onesie in rows! Too cute! Bottom of page, she tells how she hoops them. Look for Embellishing Onesies.

good question and you got good answers so here are flowers for you all