Anatase TiO2 nanoparticles have been successfully synthesized at 130 A degrees C for 2 days via ionic liquid-assisted hydrothermal method. The obtained products are characterized using various techniques. The X-ray diffraction data reveal that the nanoparticles are anatase TiO2. FTIR spectrum shows that the presence of ionic liquid and indicates Ti-O-Ti peak at around 398 cm(-1), and the bands at 1500 and 1600 cm(-1) indicates C-H in-plane vibrations and stretching of imidazolium ring. Raman spectroscopy show bands at 142, 393, 513, and 636 cm(-1) reveal crystalline anatase phase. UV-Vis spectroscopy shows the lambda (max) at 355 nm corresponding to a band gap of 3.49 eV. TEM images reveal that the average diameters of anatase TiO2 nanoparticles are in the range 50-100 nm. Anatase TiO2 exhibited excellent photocatalysis for the degradation of organic dye.