A number of ways.

You can label each axis to show which series are on that axis, and you may
be able to emphasise this with colour-coding the axis label & the format of
the relevant series.

The legend puts those series which are on the primary axis before the
secondary axis ones, and you can separate them by including a dummy series
between them (with, if you wish, invisible line and symbols, and a blank
series title).
--
David Biddulph

"Tim" wrote in message
...
Excel 2007.

How can i indicate on a chart which series is using which y-axis when I
have
a secondary axis? For example I have several series on a line chart, some
using the primary axis and some using the secondary axis. If I use the
legend
it bungs them all together with no indication which axis which line is
using
- I can change their order in the legend but this doesn't really help.
This
seems to be a fundemental flaw with the legend - how are you supposed to
tell
what is happening on a chart when you have no idea which y-axis is used by
each line??? The only way I can see to do it is to get rid of the legend
(obviously a useful feature then!) and create my own legends out of text
or
shape boxes.