Relations between beads formation and jet profiles, and beads formation and electric discharge during electrospinning were investigated by changing sample parameters and spinning conditions. The jet profiles were obtained as a function of the position along the spinning line by using photographs. As the molecular weight or concentration increased, the elongational viscosity of jet at the onset of bending instability was increased, and beads formation was suppressed. In addition, beads formation was enhanced with increasing voltage. The electric discharge spark from the apex of cone was observed by using image intensified highspeed camera. It was found that the beads were also formed easily when the electric discharge generated. POLYM. ENG. SCI., 50:1788-1796, 2010. (C) 2010 Society of Plastics Engineers