The effect of alumina precursor on the synthesis of nanosized LaAlO3 powders by reverse micelle process has been studied. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis, X-ray diffraction analysis and transmission electron microscopy. Differential thermal analysis showed that LaAlO3 phase transformation occurs at 830 °C and 866 °C for Al(NO3)3 and AlCl3 precursor respectively. With Al(NO3)3 as starting precursor, well-crystallized LaAlO3 phase was formed at lower temperature. Use of AlCl3 as precursor resulted in bigger particle formation (∼41 nm) while Al(NO3)3 forms much smaller particles (∼28 nm) as confirmed by transmission electron microscopy.