Grain boundary segregation of such impurities as phosphorus, sulfur, etc., are well known as the intergranular embrittling elements in steels. Also segregation is probably the foremost explanation for the formation of intergranular fracture surfaces. However, the fabrication of this type of fracture surface may be effected by a number of parameters including grain size and cementite shape. The interaction of segregated phosphorus and other metalloid impurities, especially carbon, is of particular interest. A number of papers showed site competition between these elements in the grain boundaries. Carbon expels phosphorus from the grain boundaries and changes the fracture mode from intergranular to transgranular. In the present work the authors aimed to compare the influence of shape and distribution of carbide particles on the formation of a brittle fracture surface of steels embrittled by phosphorus. Two kinds of cementite -- spherical and lamellae with two types of spherical cementite distribution: uniform and within grain boundaries -- have been observed.