You test confirm what I wrote (the value of the Multi-
Select ListBox is always Null).
Of course it is possible to store the values selected but
you will need to consider how to store the multiple values
selected since you can select multiple items in a Multi-
Select ListBox.
For example, you can modify the code in the link I posted
to create a list of values selected. However, you should
NOT store these values as a list since the first Principle
of the Relational Database Design Theory (RDDT) states
that "data should be atomic" meaning each Field Value (in
a Table) should only store a *single* item of data, NOT a
list of items / values.
Perhaps, you need to look up on RDDT and decide how you
should store these values in an appropriate Table
Structure first before worrying about the GUI.
HTH
Van T. Dinh
MVP (Access)