BaTi5O11 powders with microwave dielectric application potentials were synthesized using the homogeneous precipitation method and characterized. The precursor of the powders was prepared by co-precipitation of a solution of barium and titanium species with oxalic acid at a temperature of 80°C and subsequent calcination at different temperatures. The phase evolution and characteristics of the samples were studied using differential thermal analysis. Fourier transform infrared spectroscopy, x-ray diffractometry, and transmission electron diffraction. The results show that formation of BaTi5O11 starts around 700°C and continues until 1100°C in air, and in this calcination temperature range all powders appear to be single-phase, monoclinic BaTi5O11. Scanning electron microscopy and transmission electron microscopy observations reveal that the sizes of the particles, nearly round in shape, formed due to agglomeration, are about 100 nm at a calcination temperature of 700°C, and 600 nm at 1100°C.