The characterisation and spatial manipulation of cells by AC electrokinetic methods such as dielectrophoresis and electrorotation is well established. However, applications to submicroscopical objects like viruses and molecules have been rare. Only recently has the number of such studies risen more quickly due to the availability of suitable electrodes and a growing need for single molecule techniques. Of special interest is the spatial control of single DNA molecules for genetic investigations as well as for the building of well defined structures with nanometre resolution. Here a review is given of dielectrophoretic studies dealing with single and double stranded DNA emphasising single molecule aspects.