Chitosan-ZnO nanostructures are prepared by eco-friendly way of synthesis. With same amount of chitin, three different ratios of zinc chloride and sodium hydroxide concentrations are used for preparation. The hexagonal shape of chitosan-ZnO nanostructures with size range of 40-100 nm are confirmed by transmission electron microscopy (TEM). Surface morphology is characterized by scanning electron microscopy. Maximum Zn/O atomic ratio of 77:23 is noticed by energy dispersive X-ray (EDAX) analysis. Presence of chitosan and ZnO structure are confirmed with FUR spectra. Absorbance at 364 nm in the UV-vis spectra indicates the presence of ZnO. X-ray diffraction pattern indicates the size of crystallites are in 16-53 nm range. Optical studies revealed that chitosan-ZnO nanostructure with band gap of 3.4 eV have been prepared by slow addition of 45% sodium hydroxide into 15% zinc chloride and chitin solution. (C) 2011 Elsevier B.V. All rights reserved.