Resumen: [EN] In this paper, a new class of sets called μ-generalized closed (briefly μg-closed) sets in generalized topological spaces are introduced and studied. The class of all μg-closed sets is strictly larger than the class of all μ-closed sets (in the sense of Á. Császár). Furthermore, g-closed sets (in the sense of N. Levine) is a special type of μg-closed sets in a topological space. Some of their properties are investigated here. Finally, some characterizations of μ-regular and μ-normal spaces have been given.