The combination of fibre optics with micro- and nano-structure technologies offers great potential for the realisation of novel sensor concepts. Selected examples of advanced optical fibre sensor systems based on sub-wavelength structured components will be presented. Such examples are highly sensitive extrinsic fibre-optic humidity and hydrocarbon sensors for application in gas industry and in environmental monitoring using nano-porous thin-film Fabry-Perot transducer elements, or intrinsic fibre Bragg grating sensor networks for structural health monitoring (i.e., monitoring mechanical strain and deformation, vibration, temperature) in electric power facilities, aerospace, railways and geotechnical engineering as well as for chemical detection (e.g., hydrogen). Additionally, new concepts for chemical and biochemical sensing applying plasmonic metal nano-particles, photonic crystal fibres, and optical nano-wires will be discussed.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.