The hydrothermal synthesis of CuAPO-5 molecular sieves has been investigated by using Cu(II) oxide in the presence of tetraethylammonium hydroxide as a template. The CuAPO-5 material was characterized by X-ray powder diffraction, FT-IR spectroscopy, scanning electron microscopy, and elemental analysis. Supporting evidence for the framework location of copper was obtained from electron spin resonance and electron spin-echo modulation spectroscopy experiments.