CePO(4):Tb/LaPO(4) nanowires with a core/sheath architecture have been successful synthesized by a facile aqueous chemical method mediated by original CePO(4):Tb aggregation seeds. The seed crystals serve as both a luminescence center and a nucleation site for epitaxial growth. The seed nanocrystals have an irregular sphere-like shape with an average size of around 6.8 nm and a narrow size distribution. When the seed crystals are coated with LaPO(4), the resulting core/sheath CePO(4):Tb/LaPO(4) nanowires have mean diameters of about 7.6 nm and lengths up to 331 nm. Both photo- and x-ray luminescence demonstrate that the LaPO(4) coating increases the luminescence efficiency. These core/sheath structured nanowires may find potential applications in solid state lighting, medical imaging and radiation detection.