> I've just started learning O'Caml. I've written a simple factorial
> function (no checking whether n is 1 etc.):
>
> let rec factorial n =
> 	n * factorial (n-1);;
>
> When I call this function with let's say 5 as an argument, I get an
> overflow error message.
>
> Any ideas?
>
You haven't defined a stop condition, so it's going down and down into the
negatives until it overflows.

~~ Robert.