Formation of porosity in orthocoking, semicoking and gas coals during their carbonization at 100-1000degreesC (100degreesC intervals) was studied. The volumes of submicro-, micro-, meso- and macropores (respective width: < 0,4, 0.4-2, 2-50 and < 50 nm) were evaluated by CO2 and C6H6 adsorption methods, combined with mercury porosimetry. During carbonization, mainly submicropores and macropores especially in the gas coal were developed. With raising carbonization temperature, an increase in submicro- and macropores took place until a maximum volume was reached. Further increase of the temperature resulted in a slight lowering of the macropores volume, accompanied by a drastic closure of submicropores. The temperature corresponding to the highest development of submicropores decreased with increasing coalification degree of the coals.