The fabrication of electrospun composite nanofiber mats used as drug delivery systems with controlled release property is of general interest in biomaterial sciences. The aim of this study was to investigate the effect of MWCNTs on the release profile of the hydrophilic drug. For this aim, tetracycline hydrochloride (TCH) loaded poly (lactic acid) (PLA)/polyvinylpyrrolidone (PVP)/TCH-multiwall carbon nanotubes (MWCNTs) composite fibrous mats were fabricated by electrospinning process, and the drug release profile, release kinetics and cytotoxicity were evaluated to determine the potential for utilization as drug delivery systems. Furthermore, the morphological and physicochemical properties of the composite PLA/PVP/TCH-MWCNTs fibrous mats were characterized. The results demonstrated that TCH and MWCNTs were successfully loaded into the PLA/PVP biopolymeric matrix and the addition of TCH or MWCNTs did not alter the uniform and beadless fibrous structure of the PLA/PVP fibers, resulting in increased Young's modulus and maintained the fibrous structure of the composite mats. Moreover, MWCNTs loaded electrospun mats showed much more controlled drug release manner, increased significantly the drug encapsulation efficiency and reduced the burst release of TCH. In vitro cytotoxicity assay showed that the PLA/PVP/TCH-MWCNTs composite mats did not have a toxic effect on the human umbilical vein endothelial cells (HUVECs). With the improved physicochemical and mechanical properties, controlled drug release-profile and cytocompatibility, the fabricated composite nanofiber mats may be used as therapeutic materials for the biomedical applications as drug delivery systems.