The unique properties of carbon-nanotube (CNT)-doped polymers have generated several promising applications including gas sensors, high-strength/light-weight materials, and electromagnetic interference shielding. The ability to process CNT-doped materials into complex architectures may enable further advancement of these devices. We have developed a directwrite technique for processing CNT-doped poly(methyl methacrylate) (PMMA) into 3D arrays of precisely-positioned, semiconductive fibers with micro- and sub-microscale diameters. In this method, a programmable micromanipulator- controlled syringe was loaded with solvated CNT/PMMA and utilized to draw an array of freely-suspended solution filaments on a substrate in a "connect-the-dots" fashion. As the filaments are drawn, they are thinned by surface tensiondriven necking as they dry and form solid fibers. The degree of thinning can be controlled by varying the PMMA concentration or the fiber length.