Biosensors are devices that involve the selectivity and specificity of biological systems and the ability of a transducer to convert biological information in a signal proportional to the analyte concentration. Usually the biological component of a biosensor is a macromolecule or a cell that recognizes a target molecule. The biochemical changes that result from this interaction are converted by the transducer into a signal that is amplified and recorded. Herein, we describe the current status and potential applications of whole cell biosensors, examine methods currently being explored, and discuss the potential impact of such technologies. Recent reports of novel or refined strategies of biosensor design are also presented. © 2012 Nova Science Publishers, Inc. All rights reserved.