Using the electrospinning technique, we have prepared lithium perchlorate (LiClO4) doped-polyethylene oxide (PEO) electrospun nanofibers for humidity sensing and camphosulfonic acid (HCSA) doped-polyaniline (PANI)/polystyrene (PS) electrospun nanofibers for sensing hydrogen peroxide (H2O2) and glucose. The diameters of these as-prepared polymeric nanofibers are in the range of 400-1000 nm. Owing to the large surface area and good electrical properties intrinsically associated with these nanoscale functional polymer fibers, we achieved significantly enhanced sensitivity for the nanofiber sensors in respect to their corresponding film-type counterparts. While scanning electron micrographs showed some distortions for the LiClO4 doped-PEO nanofibers after the humidity measurements, no observable morphological change was seen for the HCSA doped-PANI/ PS nanofiber sensors after the measurements of H2O2 and/or glucose.