In this review we present a unified approach for single cell dielectric spectroscopy. Impedance spectroscopy and dielectrophoretic cell sorting, current microtechnologies applied in electrical analysis of single cells are discussed based on their closely related physical principles. In addition, examples of microfluidic devices will be presented: a microfabricated flow cytometer for single cell discrimination based on impedance analysis and a miniaturized continuous dielectrophoretic cell sorter, both using the concept of liquid electrodes. Using the experimental results obtained from both microdevices, we give a comparative overview over the dielectrophoretic sorting and impedance spectroscopy.