The effect of drying conditions and the first- and second-heat treatment on the structural, electrical and optical properties of ZnO thin films prepared by the sol-gel method was investigated. ZnO films were deposited on silica glass substrates by the spin-coating method. Zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine were used as a starting material, solvent and stabilizer, respectively. ZnO films were dried at 350degreesC and then heated at 600degreesC showed an extremely sharp (0 0 2) peak in the XRD patterns. The more films were oriented preferentially along (0 0 2) direction, the greater their electrical and optical properties became, By applying the second-heat treatment in nitrogen with 5% hydrogen at 500degreesC, the grain size of films was increased, the resistivity value was 0.099 Omega cm and optical transmittances became higher than 85% in the visible range. (C) 2002 Elsevier Science B.V. All rights reserved.