The minimum concentration (C-i) required for electrospinning polymeric fibers from solutions of mixtures of poly(vinyl phenol) and poly(vinyl pyrrolidone) has been experimentally determined for different blend compositions. This minimum concentration C-i has its lowest value when the polymers are mixed in a 1/1 molar ratio. This article shows different results that seem to indicate that the strong hydrogen bonding interactions between the two polymers and the corresponding higher apparent molecular weight cause the reduction of the C-i value. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2922-2928, 2009