"Gr\"{o}bner Bases in Fractional Polynomial Rings and their Applications" Giuseppa Carra'-Ferro. Department of Mathematics, University of Catania, Italy Viale Andrea Doria 6 Catania, 95125 Italy E-mail:carra@dipmat.unict.it A fractional polynomial is a generalization of a polynomial, in which nonnegative rational exponents are allowed \cite{WA1}. Many properties of polynomial rings are not true any more in this generalization, while some other property holds. In particular, given a finitely generated ideal I in a fractional polynomial ring with coefficients in a field, it is possible to extend the notion of Gr\"{o}bner basis. The aim of the paper is to show this extensions and its use for solving fractional polynomial systems.