In order to understand the role of fluorine incorporation on the structure of fast ion conducting lithium berate glasses, the binary xLi(2)O .(1-x)B2O3 glasses with x = 0.3, 0.4 and 0.5 have been fluorinated and studied using variety of experimental techniques including X-ray photoelectron spectroscopy (XPS), infrared spectroscopy, complex impedance measurement and X-ray diffractometry (XRD). XPS results have shown that O Is spectra could be described in terms of bridging (BO) and non-bridging oxygens (NBO). The ratio of these two seems to increase with increase in Li2O content. However, this ratio decreases with the increase of fluorine content. F Is XPS spectra consist of two peaks showing clearly the existence of two different fluorine environments. It was found that with increase in fluorine content the number of four-coordinated boron atoms increases and the BO3 groups with non-bridging oxygen atoms decreases. These results provide definite evidence for fluorine participation in the boron-oxygen network. These structural modifications are found to affect the glass transition temperature T-g. de conductivity of fluorinated lithium berate glasses decreases with the increase of fluorine content. Results from XPS, conductivity and DSC measurements are correlated.