Biodegradable block copolyesters are processed from water to water-stable electrospun fibers without use of any organic solvent, which is of major importance for a variety of applications. The copolyesters (poly(epsilon-caprolactone-b-methoxypolyethylene glycol)) (PCL-b-MPEG)) are emulsified in water at 90 degrees C in presence of poly(ethylene oxide) (PEO) using melt dispersion method. Dramatic increase in viscosity is observed upon addition of PEO to aqueous dispersions of copolyesters. Evidence of structure formation in aqueous PCL-b-MPEG/PEO dispersions is adduced using rheological studies. PCL block length dependent water stable nanofiber non-wovens are obtained upon electrospinning of the dispersions.