Mesoporous silica spheres (seeded by silicalite-1 nanocrystals) were converted to zeolite in a solution containing TEOS as silica source and producing zeolite hollow spheres with diameter in the 2–4 μm range. These spheres were characterized on the propane and 1,3,5-triisopropylbenzene (TPB) single gas adsorption. Propane adsorption on the hollow silicalite-1 spheres was higher than on their precursor mesoporous silica spheres, but similar to that of the silicalite-1 crystals, which indicates a weak influence of the hollow nature of silicalite-1 spheres for such a small molecule. Instead, TPB adsorption on the hollow silicalite-1 spheres was higher than that of silicalite-1 crystals and different to mesoporous silica spheres. The potential advantage of hollow silicalite-1 spheres in the storage and control release of big molecules was shown.