Double-Needle Ladder Stitch
Using two needles, one threaded on each end of the thread, pass one needle through one or more beads from left to right and pass the other needle through the same beads from right to left. Continue adding beads by crisscrossing both needles through one bead at a time. Use this stitch to make strings of beads or as the foundation for brick stitch. (Top illustration)
Single-Needle Ladder Stitch
For a single-needle ladder, string 2 beads and pass through them again. String 1 bead. Pass through the last stitched bead and the one just strung. Repeat, adding one bead at a time and working in a figure-eight pattern. (Bottom illustration)
Ladder stitch is often used as a foundation stitch for brick stitch and herringbone stitch. A common variation is to use stacks of 2 of 3 beads for a taller ladder.