The thread you choose for your bead embroidery project will have a major influence on the final appearance. Weight, color and fiber content are all factors worthy of consideration. You’ll need to get the thread through the needle. The threaded needle must pass through the bead (some very small), often in multiple passes for back stitch. Bits of the thread will be visible on the surface of the work. 

Chances are you'll be using a traditional embroidery needle, a bead embroidery needle, a glover, singly or in combination. ALL have small eyes, especially the glovers. 

Nylon beading thread is the standard choice. Size B works well for most beads and techniques and can be doubled. Size D is essential where strength is needed. 

Fireline (a very fine fishing line, translucent or dark) can be used where the finished piece will be subjected to movement. I rarely use Fireline; it has an oily surface treatment that must be wiped off before you use it. There are different weights—4 pound test for general beading use and 6 pound test for greater strength. 

Coordinating the color of your thread to the color of your beads will dramatically improve the outcome. If you’re back stitching a line of blue bads, use a similar color thread. In my kits I generally include a neutral gray or tan, depending on whether the dominant color tone of the design is cool or warm. Beading nylon comes in a wide range of colors, often in assortments based on color tones. You can use multiple colors of thread within one project, and while the back of your piece will look like chaos unleashed, the front will be beautiful.

Lately I’m experimenting with polyester sewing threads as an alternative to beading nylon. The color range is astonishing, availability is great and often local in fabric stores, and the thread’s qualities are similar to nylon. With both, I always give a good tug on the cut length to snap out any stretch or kinks. 

Polyester and nylon are both forever threads—they will not rot over time as silk and cotton may. So if you’re creating a legacy piece, perhaps a small wedding handbag to be passed through generations, a synthetic thread will be a good choice.