The specific effects of various nanoparticles on processes occurring in the electrochemical analysis of biological samples are considered. The material classification is based on a structural principle of the organization of a sensing element. Nanoparticles can occur immediately on its surface or in the bulk of an analyte (in the latter case, they can be chemically bound to the surface); they can be incorporated into the analyte and serve as its labels. The use of nanoparticles significantly extends the capabilities of bioelectrochemical methods of analysis. In a number of cases, the use of nanoparticles provides an opportunity to abandon the use of enzymes; this is very promising for clinical analysis. Methods for the electrochemical analysis of biological samples with the use of nanoparticles can be a serious addition to classical biochemical methods.