AC electric fields ware applied to suspensions of giant lecithin vesicles observed under a phase contrast microscope. Elongated vesicles were found to align parallel to the field. In sufficiently strong fields the vesicles opened at both ends and became cylinders which in some cases were immutable under further increase of the field. The cylinder parameters can be used to calculate the edge energy of the cylinder wall. For the single bilayer we obtain 2-10-6 erg cm-1.