In this study, gelatin, was successfully electrospun from a newly developed water-based co-solvent composed of ethyl acetate and acetic acid in water. Since natural polymers including gelatin exhibit limited solubility in water, toxic or highly acidic solvents are normally used to dissolve them for electrospinning. Instead of using those solvents, we used ethyl acetate in concert with acetic acid in water, and investigated the beneficial effect of its use in terms of the spinnability of the nanofiber and the acidity of the solvent. The replacement of acetic acid with ethyl acetate was observed to improve the spinnability of the nanofiber by reducing the surface tension of the solution as well as to increase the pH of the solvent significantly. The optimal composition of the co-solvent was found to correspond to a ratio of ethyl acetate to acetic acid of 2:3. Under this solvent condition, the gelatin could be dissolved at concentrations of up to approximately 11 wt% and electrospun successfully to produce nanofibers with various diameters (47-145 nm on average) depending on the gelatin concentration. The water-based co-solvent method proposed herein may be useful for generating other nanofibrous natural polymers as well as being applicable in delivery systems for bioactive molecules within the nanofiber matrices.