Hi Andreea

A listbox has a property called "MultiSelect". If you set this property to
Extended, you will be able to select multiple items in that box with using
Ctrl or Shift. But this is not the end of the story. Access does not
conveniently combine or concatenate the result for you, you would have to
loop through each selected item and do something with it.

Below is an example of a form called SomeForm and a listbox within that form
called SomeListBox (aircode - just off the top of my head to give you an
example). The example goes through each selected item and simply combine
(concatenate) them.

   Dim frm As Form, ctl As Control
   Dim varItm As Variant
   Dim varSelectionResult as Variant

  Set frm = Forms!SomeForm
  Set ctl = frm!SomeListBox

  For Each varItm In ctl.ItemsSelected
       varSelectionResult = varSelectionResult  & ctl.ItemData(varItm)
  Next varItm

  ....   do whatever you need with varSelectionResult

That said, I have to bring up table normalization. Needing multiple values
in a column for a row suggests an unnormalized table which will create
problems. In a normalized table, you should only find ONE value at an
intersection between a column and a row.

HTH,
Immanuel Sibero