Fiber based nanophotonic devices consist of microstructured optical fibers which included nanoscale elements. One implementation approach relies on placing desired materials into the subwavelength holes of photonic crystal fibers (PCFs). In this talk, I will review our recentresults on plasmonic PCFs, semiconductor fibers, highly nonlinear chalcogenide‐silica waveguides and opto‐fluidic fiber form sensors. As examples, we observe spiraling planar plasmonic modes, very broad super‐continuum generation, octave‐spanning azimuthal mode polarization, distinct Mie‐resonances and strong photonic band gaps. Furthermore, I will give an outlook about future experiments and potential integrated devices.