The effect of nonsolvent on morphologies of electrospun polyamide 6 (PA6) fibers was reported in this study. An investigation of electrospinning PA6 / formic acid (FA) / dichloromethane (DCM) solutions was conducted, wherein FA was used as solvent and DCM was used as nonsolvent for PA6. It is interesting to note that PA6 pellets could dissolve in FA/DCM mixtures with various volume ratios faster than in pure FA. Moreover, the addition of DCM to PA6/FA solution modified the solution properties, that is, conductivity, surface tension, and viscosity. It is found that at any fixed PA6 concentration, the conductivity values and surface tensions values of PA6/FA/DCM solution reduce significantly, whereas the viscosity values of PA6/FA/DCM solution increase significantly, as the volume fraction of DCM in FA/DCM increase. The influences of mixed solvents component on morphological appearance and sizes of the resulting PA6 electrospun fibers were also investigated. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3005-3012, 2010