Nano-crystalline particles of CeO2 have been synthesized via a low temperature hydrothermal synthesis process. Two types of precursors were studied—cerium hydroxide and ceria acetate. The precursors were adjusted to a basic (pH 10) and acidic (pH 4) medium before hydrothermal treatment at various durations of 6, 12, 18, and 24 h at 250 °C using a Teflon-lined hydrothermal bomb. The synthesized samples were characterized using DTA/TGA, XRD and TEM. Based on the characterization results, both precursor systems produced crystalline ceria nano-particles after 6 h of hydrothermal synthesis at 250 °C. The average crystallite sizes were 6 and 15 nm for the hydroxide and acetate system, respectively. The acetate precursor system appeared to produce better particles in terms of crystallinity and morphology. Based on the DTA/TGA analysis, hydrothermal synthesis had been effective in reducing the amount of intermediate products. With increasing hydrothermal treatment duration of up to 24 h, the samples did not exhibit a remarkable improvement in properties. The synthesized nano-particles were subsequently heat treated at 500 and 1000 °C for 2 h. After the heat treatment, enhanced crystallinity and growth in crystallite size was observed, but particles appeared more agglomerated.