Working at the Y: Zeolite Y crystals with micropores (ca. 1 nm), small mesopores (ca. 3 nm), and large mesopores (ca. 30 nm) were obtained by base leaching of previously steamed and acid-leached material. The zeolite Y crystals with trimodal porosity (see electron-tomographic picture) displayed close to ideal hydrocracking selectivity and enhanced yields of kerosene and diesel.