Noble metals, such as Pd, Ag, Pt, Au and Ru, are known to be very effective catalysts and help in the improvement of the metal oxides sensing properties. A series of methods have been proposed to incorporate these metals into oxides nanostructures to improve the sensing performances. Enhanced properties were obtained for nanosensors based on a single nanowire (NW) of noble metal-doped zinc oxide as well as for noble metal - functionalized one. Crystalline nanowires of semiconducting oxides were synthesized by thermal growth or electrodeposition and studied by scanning electron microscopy SEM, EDX, TEM, HRTEM, SIMS, X-Ray photoelectron spectroscopy, PL and micro-Raman spectroscopy. Integration of a single NW on the chip was performed by using metal maskless nanodeposition in the dual beam focused electron/ion beam instrument. The ultraviolet (UV) and gas response were studied for nanosensors based on a single NW. We found that ZnO:Ag NW based nanosensors possess a much faster response/recovery times than those reported in literature. Also, nanosensors based on a single CuO NW or Fe2O3 NW have been successfully fabricated and studied in details. The developed nanosensors are of high scientific and engineering interest as candidates for fabricating multifunctional detectors.