To date, the aggregated nanostructures of conjugated polymers have been actively investigated as active materials, displaying promising optical and electrical properties and as good candidates for developing potential applications in electronics, optics, photovoltaic cells, and biology. This paper presents a review of the works on low dimensional nanostructures (nanowires, nanotubes, nanobelts, and nanofibers) of p-conjugated polymers. The diverse preparation methods were discussed, including hard and soft template-assisted synthesis, electrospinning, nanolithography, self-assembly at interfaces, in solution and in solids, and other strategies. Their potential applications in the fields of light-emitting diodes, field emission devices, organic photovoltaics, sensors and nanoelectronics are shown.