We demonstrate here the application of electrochemical impedance spectroscopy (EIS) in microfluidic devices for label-free virus identification by means of their specific signature and also investigate its feasibility for titer quantitation using two basic approaches. The first one is a method based on identifying so-called resonance frequencies manifesting in our microdevices and monitoring their variation as a function of the virus concentration, whereas the second one relies on measuring the relative impedance variation at these resonance frequencies. Best results have been obtained for the highest resonance frequency (approximate to 80 MHz), which we attribute to be due to both the structure of the microdevice and the extremely small size of the viruses that make their effect significant only at such frequencies. This is a simpler method of determining virus concentration in diluted solutions of purified viruses than the well-established traditional plaque assay titer estimation method, andsince it is based on frequency measurementcould potentially be more accurate.