Nanosized lanthanum nickel oxide powder LaNiO3 with perovskite structure was successfully synthesized at a relatively low calcination temperature by using an amorphous heteronuclear complex LaNi(DTPA) . 6H(2)O as a precursor. The precursor decomposed completely into nickel oxide above 600degreesC based on the DTA and TGA results. XRD demonstrated that nanosized LaNiO3 crystalline powder with pure perovskite structure was obtained after the calcination temperature increased to 700degreesC. The effects of calcination time and temperature were also examined by XRD and TEM. The results indicated the grain size and the crystal size of LaNiO3 increased with the calcination temperature from 600degreesC to 900degreesC, and were less influenced by the heat-treatment time. The electrical resistivity of the powder decreased when the calcination temperature increased. It can be concluded that it is a useful way to synthesize nanosized perovskite oxides using an amorphous complex as a precursor, and this method can be easily quantitatively controlled. (C) 2003 Kluwer Academic Publishers.