Assuming you have a table called tblCompanies, two of its fields being:
CompID (PK, autonumber)
CompName

Put a combo box on your form, and make its rowsource a query on the
table, including these two fields (in that order);
Set the combo box's properties as follows:
Property    On Tab        Setting
Column Count    Format        2
Column Widths    Format        0;5 (or 0;whatever)
Bound Column    Data        1

These property settings make the combo box 'include' both fields (Column
Count = 2), but only show the name (the width for the ID column is 0),
while it returns the ID field value (Bound Column = 1).
Notes on the column widths setting:
1. list separator may be comma instead of semicolon in some systems
2. the second column width setting above is just an example; experiment.

HTH,
Nikos

The user should NEVER EVEN SEE IT.

The table should probably *not* have ANY Lookup Fields, and the user
should never see a table datasheet at all. Table datasheets are good
for design and debugging; they are not designed nor intended for user
interface purposes.

The user should see a Form with a Combo Box control on it. The Combo
Box would be based on the Companies table, and would have two columns;
the numeric ID and the company name. The Column Widths property would
be set so that the user sees only the company name; the bound column
would be the (zero width) ID, and on the Form the combo would be bound
to the numeric CompanyID field.

That way the user sees "Acme Products Inc.", the computer sees 3122,
and they both are happier. <g.

                 John W. Vinson[MVP]