A new method, sol-gel autocombustion, is employed in the synthesis of magnetite (Fe3O4) by using citric acid and ferric nitrate as starting materials. Experimental results show that pure magnetite can be synthesized at a very low temperature in a large range of molar ratio of ferric nitrate to citric acid. The XRD results illustrate that the prepared samples have pure Fe3O4 phase. Electron microscopy studies show us the samples with porous morphology. VSM results show us ferrimagnetic property of the samples at room temperature with the saturation magnetization as high as 86 emu/g.