Purpose: The paper presents evaluation of influence of grain normalization (refinement as a result of repeated austenitizing), and the inclination to precipitate the hypereutektoid cementite in Widmannstaetten structure in G200CrMoNi4-6-3 cast steel. Four temperatures of heat refining have been applied. Design/methodology/approach: Basic research of G200CrMoNi4-6-3 cast steel included metallographic analysis, and hardness and impact strength tests. The heat treatment has been planned on the basis of CCT diagram prepared for that alloy cast steel. Findings: The test material has been G200CrMoNi4-6-3 hypereutectoid cast steel. The evaluation has been carried out for four annealing temperatures, i.e. 850, 900, 950 and 1050 degrees centigrade. At all annealing temperatures in the structure of cast steel the precipitation of hypereutectoid cementite along grain boundaries of former austenite took place. At the temperature of 850 degrees centigrade one may observe the coagulated hypereutectoid cementite precipitates inside of primary grains of austenite. Whereas beginning from the temperature of 900 degrees centigrade the cementite in G200CrMoNi4-6-3 cast steel forms distinct "subgrains" inside of primary grains of austenite. Research limitations/implications: Research financed by the Ministry of Scientific Research and Information Technology, grant No. 3 T08B 057 29. Practical implications: G200CrMoNi4-6-3 cast steel of ledeburite class is used mainly for rolls production. Any data related to the structure and mechanical properties of that cast steel are precious for the manufacturers and users of the mill rolls. Originality/value: The new heat treatment of G200CrMoNi4-6-3 cast steel.