Enter the "Code" criteria in C1, then try this *array* formula:

=COUNT(1/FREQUENCY(IF((B2:B6=C1),MATCH(A2:A6,A2:A6,0)),ROW( 1:5)))

--
Array formulas must be entered with CSE, <Ctrl <Shift <Enter, instead of
the regular <Enter, which will *automatically* enclose the formula in curly
brackets, which *cannot* be done manually. Also, you must use CSE when
revising the formula.


--
HTH,

RD

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"Chuck" wrote in message
...
I need to count the number of unique cases given certain criteria. For
example,

Case # Code
3356 Stroke
3356 Stroke
3357 Cancer
3357 Cancer
3356 Cancer
The results should indicate: 1 unique case for Stroke; 2 unique cases for
Cancer. Thanks for any help.