Directed assembly of triblock copolymer worms to produce nanostructured fi bers is achieved via colloid electrospinning. These copolymer worms are conveniently prepared by polymerization- induced self-assembly in concentrated aqueous dispersion. Addition of a second water-soluble component, poly(vinyl alcohol), is found to be critical for the production of welldefi ned fi bers: trial experiments performed using the worms alone produce only spherical microparticles. Transmission electron microscopy studies confi rm that the worm morphology survives electrospinning and the worms become orientated parallel to the main axis of the fi bers during their generation. The average deviant angle (theta(dev)) between the worm orientation and fi ber axis decreases from 17 degrees to 9 degrees as the worm/PVA mass ratio increases from 1.15:1 to 5:1, indicating a greater degree of worm alignment within fi bers with higher worm contents and smaller fi ber dia meters. Thus triblock copolymer fibers of approximate to 300 +/- 120 nm diameter can be readily produced that comprise aligned worms on the nanoscale.