Advanced techniques for the preparation of nanofibers, core shell fibers, hollow fibers, and rods and tubes from natural and synthetic polymers with diameters down to a few nanometers have recently been established. These techniques, among them electro- and co-electrospinning and specific template methods, allow the incorporation not only of semiconductor or catalytic nanoparticles or chromophores but also enzymes, proteins, microorganism, etc., directly during the preparation process into these nanostructures in a very gentle way. One particular advantage is that biological objects such as, for instance, proteins can be immobilized in a fluid environment within these polymer-based nano-objects in such a way that they keep their native conformation and the corresponding functions. The range of applications of such biohybrid nanosystems is extremely broad, for instance, in the areas of biosensorics, catalysis, drug delivery, or optoelectronics.