Thin fibers of calf thymus Na-DNA were electrospun from aqueous solutions with concentrations from 0.3% to 1.5%. In electrospinning, a high voltage is used to create an electrically charged jet of liquid solution, which dries to leave a polymer fiber. The electrospun DNA fibers have diameters around 50 to 80 nm. The diameter of the electrospun fibers is an order of magnitude or more smaller than that of previously reported fibers. The DNA fibers were observed by optical microscopy, scanning electron microscopy, and transmission electron microscopy. Bead-like structures were observed on many of the fibers. During electrospinning a process called splaying causes the jet to split longitudinally into two smaller jets, which split again, repeatedly, until the very small diameter fibers are formed. The small-diameter fibers are transparent in ordinary 100 kV electron microscopes. Fibers can be spun from samples of DNA as small as 1 mg.