Excel 12 will suppport 64 nested functions
http://blogs.msdn.com/excel/archive/2005/09.aspx
Until then, you have to stucture the calculation to work within current
limits, as suggested by other responses.

Jerry

Darin Gibson wrote:

I need to nest 10 IF functions.

According to Excel help:

Up to seven IF functions can be nested as value_if_true and value_if_false
arguments to construct more elaborate tests. See the last of the following
examples.

What else can I do?