Electric conductivity is considered In a wide-range of pressures and t
emperatures of non-ideal states of matter. The classification of state
s is given and a phase diagram of matter is divided into a number of d
omains dependently on a non-ideality character. After a short informat
ion on electric conductivity of an ideal plasma the most clear and con
structive theoretical models are reviewed. The experimental data avail
able are discussed and the comparison with them is given. The variatio
ns of electric conductivity are described by many orders of magnitude
with temperature and density variations.