Depending on what you use the form for, you may not actually need to see the ID number -- maybe the description would be more useful, with the ID being automatically selected.
This is what combo boxes do. If you haven't built one before, use the Wizard. Here's the process:
1. In Design view on the form, with the Wizard activated, click the Combo Box icon and then click on the form. The Wizard will launch.
2. When asked whether you want to build your own list or use values from a table or query, select the latter.
3. Scroll through the list of tables and queries, find the one that has the ID and Description, or just open the Table that contains both fields.
4. First field will be the ID, second field will be the Description. Opt to Hide Key Field.
5. When asked whether to store or keep for later use, select Store. From the list, pick the ID field.
6. Give the combo a caption. OK to save, then see how it works.
Once you're happy, delete the original text box and put the combo in its place.
Denis