Nanocrystals of LaPO4:Eu and CePO4:Tb with a mean particle size of 5 nm and a narrow size distribution have been prepared by reacting the corresponding metal chlorides, phosphoric acid, and a base at 200 degrees C in tris(ethylhexyl) phosphate. Highly crystalline material was obtained as confirmed by X-ray powder diffraction measurements and high-resolution transmission electron microscopy. Successful doping with europium was evident from the splitting and the intensity pattern of the luminescence lines. Luminescence lifetime measurements were used to confirm doping and energy transfer in both materials. Colloidal solutions of CePO4:Tb exhibit an overall luminescence quantum yield of 16%.