Ladder stitch and mattress stitch are both types of invisibile stitches used to join two pieces of fabric together. They are worked in a similar way, but there are some key differences.
With ladder stitch, the needle is passed through the fabrics from the top side, emerging at the bottom. The thread is then pulled tight, drawing the fabrics together. This type of stitch is often used for joining appliqués or other small embellishments to a fabric surface.
Mattress stitch, on the other hand, is worked from the wrong side of the fabrics. The needle emerges at the top side, and is then passed back down through both layers of fabric. This creates a small “X” on the surface of the fabric. Mattress stitch is often used for joining larger pieces of fabric together, such as when sewing a seam in garment construction.