We describe a platform for photoelectrophoretic transport and electronic hybridization of fluorescence-labeled DNA oligonucleotides in a low conductivity electrolyte. At the core of the platform is a chemicallystabilized semiconductor photodiode or photoconductor surface coated with a streptavidin-agarose permeationlayer. Micro-illumination of this surface generates photoelectrochemical currents that are used to electrophoretically transport and attach biotinylated DNA capture strands to arbitrarily selected locations. The sameprocess is then used to transport and electronically hybridize fluorescence-labeled DNA target strands to thepreviously attached capture strands. Signal detection is accomplished either by a fluorescence scanner or aCCD camera. This represents a flexible electronic DNA assay platform that does not rely on pre-patternedmicroelectronic arrays.