The False arguement was in the wrong place:

=IF(ISNA(VLOOKUP(A2,'3-16'!$L$2:$BF$1538,20,FALSE)),VLOOKUP(A2,'3-9'!$L$2:$BF$1498,20,FALSE),0)

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Best Regards,

Luke M
"Candida" wrote in message
...
i have the following formula written to compare two worksheets that have an
identical item number, however column 20 contains vital information and
must
be collaborated and tracked on a central document. So, I am trying to
combine
the information by creating a new tracking sheet with the item # in column
1
and hoping to perform a Vlookup to pull in the data from column 20 on both
work sheets, ie: if it is not on the '3-16' worksheet then pull
information
from '3-9' work sheet, or populate as "0". The following formula doesnt
seem
to be working. Please help

=IF(ISNA(VLOOKUP(A2,'3-16'!$L$2:$BF$1538,20,FALSE),0),VLOOKUP(A2,'3-9'!$L$2:$BF$1498,20,FALSE)))