Bio-impedance is the electrical impedance of living matter. Bio-impedance methods present a range of known advantages for medical and clinical applications including low-cost, non-invasiveness and harmlessness. The measured parameter reflects the physiological and pathological processes that take place within human body. The technological progress in instrumentation has significantly contributed to the progress that has been observed during the last past decades in impedance spectroscopy and electrical impedance tomography. Although bioimpedance is not a physiological parameter, the method enables tissue characterisation and functional monitoring and can contribute to the monitoring of the health status of a person. The association of this flexible and versatile method with micro-electronics and wireless telecommunication systems opens a new field of potential applications.