One way:

A1 = lookup value

B1:B10 is lookup array

=IF(COUNTIF(B1:B10,A1),LOOKUP(......),"what do you want to happen if the LU
value doesn't exist")

--
Biff
Microsoft Excel MVP


"Ken King" wrote in message
...
I am using the LOOKUP funtion for an array. Of my 300+ values I know that
about 20 'lookup_value'(s) don't exists in the array, but I don't want it
to
find the next closest value. How can I test my array to see if the
'lookup_value' exists?
Thanks,
Ken