Following a brief historical introduction on verocytotoxigenic/Shiga toxin producing Escherichia coli (VTEC/STEC), the problems of identifying these pathogens, especially those belonging to serotypes other than O157:H7 or O157:H- are discussed. The current molecular biological techniques as well as the immunologically based methods of rapidly diagnosing the presence of VTEC/STEC in both patient-derived as well as food and environmental samples are reviewed. The extent to which the methods have been fully evaluated is reviewed and the conclusions discussed. The problems of using test systems, which are not evaluated for the specificity and sensitivity with the types of clinical samples with which that laboratory is mainly concerned, are addressed as there is the risk that false-positive and/or false-negative reactions are not taken into consideration. This can result in significant consequences on patient therapy, prevention of spread of the disease and with additional costs required for retesting samples and confirmation of test results. The advisability of using a VTEC detection method that is well defined in its strengths and limitations rather than an assay system that has not been well explored for its suitability is stressed.