Nonpolar a-plane GaN films were grown on r-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The as-grown films were studied by atomic force microscope (AFM), High-resolution X-ray diffraction (XRD) and Hall measurements. The structural and electronic transport properties of the films were in-plane anisotropic. The formation mechanism of anisotropic properties was discussed. (C) 2004 Elsevier B.V. All rights reserved.