The relationship between the strength of structural 40 and 30KhGSA steels and their susceptibility to embrittlement under the circular notches with radius of 0.25 mm and 2 mm is investigated on cylindrical specimens with an initial diameter of 8 mm. The parameter of susceptibility to embrittlement is determined by both changes in ductility of specimen and by measuring of difference in ratios of fracture stress to yield stress of specimens before and after notching. As shown, despite the almost fivefold increase in strength of steel, the parameter of susceptibility to embrittlement is really stable by strength characteristics over the range 0.3—0.4 and slightly depends on the notch sharpness. Effect of susceptibility to embrittlement of steel measured by steep decrease in ductility reaches 70—90% for high strength levels and significantly depends on the notch sharpness. As ascertained, the significant embrittlement effect of notches is caused by, first, the stress concentration factor and less depends on the strength and ductile properties of steels.