The only build-in functionality that can do this is Data, Filter, Advanced
Filter. This requires that you copy and paste the two lists together to
make one list. There should be one row per contact like:

Name1 Address1
Name2 Address2
etc.

Once you arrange the data this way you can use the above command, selecting
the Copy to another location and Unique records only options. Any identical
records (all fields being the same) will be listed only once, eliminating
duplicates.

--
Jim
"Peterd35" wrote in message
...
|I have two key contacts spreadsheets with names, addresses etc, which I now
| want to combine, adding one to the other, not overwriting unless the data
is
| the same.
| Can I do this in Excel?