The present review describes the data on electrochemical reduction of cytochrome P450. Three generations of enzyme biosensors have been considered. The concept and potentialities of enzyme electrodes - transducers - as the main element on construction of electrochemical biosensors are described. Different types of electrodes for bioelectrochemistry are presented. New experimental approaches for immobilisation of cytochrome P450 based on nanotechnology are reported. Nanobiotechnology in electrochemistry has potential application for production of biosensors and bioreactors for medicine.