The present invention concerns a catalyst comprising at least one crystalline material comprising silicon with a hierarchical and organized porosity and at least one hydrodehydrogenating element selected from the group formed by elements from group VIB and/or group VIII of the periodic table of the elements. Said crystalline material comprising silicon with a hierarchical and organized porosity is constituted by at least two spherical elementary particles, each of said particles comprising a matrix based on oxide of silicon, which is mesostructured, with a mesopore diameter in the range 1.5 to 30 nm and having microporous and crystalline walls with a thickness in the range 1.5 to 60 nm, said elementary spherical particles having a maximum diameter of 200 microns. The invention also concerns hydrocracking/hydroconversion and hydrotreatment processes employing said catalyst.