Biocompatible and pH-sensitive poly (N-isopropylacrylamide-co-methacrylic acide-co-vinylpyrrolidone) [P(NIPAAm-MAA-VP)] nanofibers were prepared as a delivery vehicle for sustained release of doxorubicin hydrochloride (DOX) as an anticancer drug. The structure and morphology of nanofibers were investigated by SEM, FTIR, and XRD. P(NIPAAm-MAA-VP)-DOX complex was formed at pH 7 because of ionic interactions between DOX and polymers. P (NIPAAm-MAA-VP) nanofibers tailored to desire diameters with bead free morphology by optimizing the electrospinning parameters DOX release from P (NIPAAm-MAA-VP)/DOX complex was investigated as a biological on-off switch for the design of an intelligent drug delivery system triggered by external pH changes.