I think SUMIF will only deal with one condition.
Try
=SUMPRODUCT((A1:A20000<"Jason")*(A1:A20000<"Mich ael"))
Adjust to suit, note that SUMPRODUCT will not work with whole columns (A:A)
etc, it has to be a specified range like A1:A36000, the same range of rows
must be used in all columns. This is well documented in help, post back if
you have a problem,
Regards,
Alan.
"Marina" wrote in message
...
I am trying to sum column I based on the rows that do not have either Jason
or Michael in column D.

=SUMIF('Master Client List-do not edit'!D:D,"<Jason""<Michael",'Master
Client List-do not edit'!I3:I65535)

However, the above formula is giving me the results number of unique #rows
not equal to Michael and #rows not equal to Jason (i.e. all rows because
it
sees it as an OR rather than an AND).

What is the correct formula?

Marina