The rapid and accurate detection of pathogenic Escherichia coli (E. coli) poses a significant health problem in both developed and developing countries around the world. Conventional microbial detection methods can take more than 48 hours to identify a pathogenic organism. Recently new types of nucleic acid chip based methods, microfluidic devices, signal amplification methods, immunoassays and biosensors have been developed capable of detecting very low concentrations of pathogenic E. coli in a few hours. This review examines the current limitations and recent advances in methodologies employed in the rapid detection of pathogenic E. coli O157: H7.