Dim ListRange As Range, c As Range
' change the below to match your data's range
Set ListRange = ThisWorkbook.Sheets("Sheet1").Range("A1:A10")
With ListBox1
.RowSource = "" ' clear the RowSource, if set
.Clear ' clear ListBox
.AddItem "All" 'Insert "All" item
For Each c In ListRange
.AddItem c.Value ' Insert the values from ListRange
Next c
.ListIndex = 0 ' Select the first item ("All")
End With