Hollow SnO(2) spheres with smooth surface have been fabricated by a low temperature template-free solution phase route via self-assembly of small nanocrystalline particles. These hollow spheres have a very thin shell thickness of about 10 nm and are built from SnO(2) nanocrystals of an average size of 5.3 nm. The evacuation behavior of inside-out Ostwald ripening can be used to explain the formation of hollow spheres according to results of time-dependent reactions. The cathodoluminescence spectrum indicates a blue shift of the band gap emission peak of SnO(2), originating from quantum confinement effect due to the nanoscale size of SnO(2) particles. The as-prepared SnO(2) hollow spheres were also found to exhibit excellent performance in wastewater treatment.