Using small angle X-ray scattering (SAXS) data recorded by E.Wojciechowska et al. for iPP/PLAfibers, we have computed microstructural parameters by simulating SAXS pattern employing one-dimensional HosemannÂs paracrystalline model. For this purpose we have used the SAXS data of the fibers containing 100wt% of iPP and 40wt% of PLA. The supramolecular structure of fibers was correlated in terms crystalline and amorphous phase lengths. It is observed that there are significant changes in phase lengths owing to the presence of biodegradable PLA when compared to polypropylene fibers.