The mattress stitch is one of many techniques for joining two pieces of knitting in a way that’s often nearly invisible. You start by finding the bar that’s between the stitches just past the first row of stitches at the edge. You can see the bars in the image below:

Then with the two pieces of work side you’re joining held by side, use the yarn with a sewing needle to go down behind the bar on the left piece of knitting, then down behind the bar on the right piece of knitting. After going back and forth, you’ll see the zig zags across the gap as shown below:

Then when you pull yarn tight, the stitches disappear and the result is a beautiful seam!

Video Tutorial
The following video shows you all the steps of sewing the mattress stitch:
Want to Give it a Try?
This mitten ornament is sewn shut with the mattress stitch.