One way:

=MIN(IF(B1:B100<0,ROW(B1:B100)))

Array-entered, meaning press ctrl/shift/enter.

HTH
Jason
Atlanta, GA

-----Original Message-----
I have two column A and B. Column A contains ascending
numbers from 1 to 100,
column B contains arbitrary values. What is the function
that looks for the
first nonzero value in column B (going from the frist to
the last row) and
returns the value of column A of the same row.
.