The objective of this study was to produce biocompatible plasma-treated and silk-fibroin (SF) modified poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofiber mats. The mats were plasma-treated using O-2 or N-2 gas to increase their hydrophilicity followed by SF immobilization for the improvement of biocompatibility. Contact angle measurements and SEM showed increased hydrophilicity and no disturbed morphology, respectively. Cell proliferation assay revealed that SF modification together with N-2 plasma (PS/N-2) promoted higher osteoblastic (SaOs-2) cell viability. Although, O-2 plasma triggered more mineral formation on the mats, it showed poor cell viability. Consequently, the PS/N-2 nanofiber mats would be a potential candidate for bone tissue engineering applications. (C) 2016 Elsevier B.V. All rights reserved.