  This paper deals with stratifying systems over hereditary algebras. In the
case of tame hereditary algebras we obtain a bound for the size of the
stratifying systems composed only by regular modules and we conclude that
stratifying systems can not be complete. For wild hereditary algebras with more
than 2 vertices we show that there exists a complete stratifying system whose
elements are regular modules. In the other case, we conclude that there are no
stratifing system over them with regular modules. In one example we built all
the stratifying systems, with a specific form, having maximal number of regular
summads.
