Hi rah,

You can add drawing objects to a chart BUT before you do have a look at
these examples of adding datum lines to charts.

Jon Peltier's example
(http://www.geocities.com/jonpeltier/Excel/Charts/ComboCharts.html#AddLine)

and one of my own
(http://www.andypope.info/charts/averageline.htm)

Hi,
You do so by using View|Toolbars and clicking Drawing.
Before you select a drawing item, click on the chart (get the 8 fill handles
to show). If you omit this, the object will float on the chart - move one
and the other stays still.
Bernard