In this paper, we critically address the reform of cassation appeal (recurso de casación) on the contentious-administrative jurisdiction carried out by Act no 7/2015 of 21th July, which amends the Judiciary (Organization) Act. We will focus on the procedural aspects and the appeal interest, one of the cornerstones of the new system. In doing so, it is considered necessary to briefly analyze the functions of the cassation appeal and its access constraints first, then undertake the study of the procedural and substantive problems that the aforementioned reform may entail.Se examina la reforma del recurso de casación en el orden contencioso- administrativo, introducido por la Ley Orgánica 7/2015, de 21 de julio, que modifica la Ley Orgánica del Poder Judicial, especialmente en lo que refiere a los aspectos procedimentales y al interés casacional objetivo.