Zinc oxide (ZnO) nanoparticles were produced using chemical precipitation synthesis with a molar ratio of 1:1, 1:2 and 1:3. The structure, chemical composition and morphology were investigated by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). XRD and EDS demonstrated that the all particles formed at different atomic proportion were of wurtzite crystal structure with the same chemical composition. SEM and TEM showed the formation of hexagonal particles with a molar ratio of 1:1 while the samples synthesized with a molar ratio 1:2 and 1:3 showed a circular shape. HRTEM and Fast Fourier Transform (FFT) demonstrated that the all particles were formed with a preferable  growth direction.