Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, 45S5 bioactive glass fibers were prepared through sol-gel processing and electrospinning technique. A precursor solution containing poly vinyl alcohol and bioactive glass sol was used to produce fibers. The mixture was electrospun at a voltage of 20 kV by maintaining tip to a collector distance of 8 cm. The fibers with an average diameter of 337 +/- 81 nm (before calcination) were successfully obtained. Results showed that the crystalline phase of the fibers was largely influenced by the calcination temperature. Hydroxyapatite formation on calcined 45S5 fibers was investigated in simulated body fluid (SBF) using different fiber/SBF (F/S) ratios (0.5, 1, 2 and 10 mg/ml) at 37 degrees C. When immersed in SBF, conversion to a calcium phosphate material showed a strong dependence on the F/S ratio. At high solid concentration (10 mg/ml), surface of the fibers could not be converted to the HA-like material in SBF after 30 days. At lower solid concentrations (2, 1 and 0.5 mg/ml) an amorphous calcium phosphate layer formation was observed followed by the conversion to hydroxyapatite. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.