Abstarct: In this thesis, Zinc oxide nano-rods (ZnO), as well as core-shell nano-structures of Zinc oxide (ZnO) and Titanium dioxide (TiO2), were synthesized by hydrothermal and sol-gel methods and structural and optical properties of the samples were investigated. The ZnO / TiO2 core-shells were prepared in two ways. In the first method for the preparation of ZnO / TiO2 core-shell nano-structures, ZnO nano-rods were first synthesized on the glass substrates by hydrothermal method. Then, TiO2 shells diluted in 2-propanol, were deposited on ZnO nano-rods by the spin coating method. In the second method, ZnO nano-powder was prepared from the solution used for the synthesis of ZnO nano-rods, then this powder was dissolved in different ratios in TiO2 solution diluted by 2-propanol. After drying the solution, the ZnO / TiO2 core-shell nano-structures were obtained. The results obtained of XRD patterns of the samples confirmed the formation of the hexagonal structure of Zinc oxide and the tetragonal structure of Titanium dioxide in the anatase phase. The lattic constants obtain from the XRD data, are consistant with the reported values. The recorded FESEM images from the surfaces of the samples confirmed formation of Zinc oxide nano-rods and the coating of ZnO cores by the TiO2 shells. Raman spectroscopy for samples were also confirmed the formation of ZnO / TiO2 core-shells. Recorded TEM images also confirmed the formation of the core-shell structure of ZnO / TiO2. In this study, the optical properties of the synthesized ZnO / TiO2 core-shells with both method were also investigated.