The ability to prepare ultrathin fibers by electrospinning of a polyelectrolyte containing amines in aqueous acetic-acid solutions and mixed aqueous acetic-acid and EtOH solutions was demonstrated. The electrospinning process was optimized using a Nanospider(TM) laboratory apparatus for needle-free spinning (Elmarco, Czech Rep.). Ultrathin fibers were prepared from 16-22% EudragitA (R) E solutions in acetic acid (70%) and a mixed solvent of acetic acid:EtOH (50:50). It was found that the thinnest nanofibers were produced by using a solvent mixture of aqueous acetic acid (5%) and EtOH.