A kinetic equation is derived which describes the behaviour of electrons in tokamaks in the presence of intensive low frequency fluctuations of electric and magnetic fields. For 'collision integrals' of particles with fluctuations some expressions of a specific character are found. A complete system of hydrodynamic equations describing the behaviour of both the electron component and the quasi-neutral plasma as a whole is obtained. Fluctuations are shown to lead not only to anomalous transport processes, but also to new essential terms in the equations for energy and momentum transport. – Fluctuations have a particularly strong effect on superthermal and runaway electrons. The distribution of runaway electrons in energy and in the tokamak cross-section is found, and the flux of accelerated limiter reaching relativistic electrons is determined. These results agree qualitatively with observations. – The essential difference in the dynamics of runaway electrons for 'collisions' with electrostatic and magnetic fluctuations is demonstrated. A quantitative analysis of these data can be used for evaluating magnetic fluctuations in tokamaks.