In this work we have examined the effects of inclusion type on the toughness of two low alloy steels. The first composition considered was (in wt.%) 0.4 carbon, 1.5 nickel and 1 chromium. The second composition was identical except that it also contained 2 wt. % silicon. For each composition three heats were prepared. One heat was not modified with any additions to getter the sulfur. The sulfides in these heats were expected to be particles of CrS. One heat was modified by the addition of 0.025 wt. % titanium in order to getter the sulfur as particles of titanium carbosulfide. The third heat was modified by the addition of rare earths so that the sulfur and oxygen could be gettered as rare earth oxy-sulfides, sulfides and oxides. Previous work has shown that small titanium additions to steels such as HY180 and AF1410 can result in the sulfur being gettered as particles of titanium carbosulfide which results in significant improvements in toughness because the particles of titanium carbosulfide are very resistant to void nucleation. In addition, previous work has shown that rare earth additions significantly improve the toughness of HY180 and AF1410 steels because such additions result in large and widely spaced inclusions. The purpose of this work was to determine if these two approaches to gettering sulfur could be used to improve the toughness of low alloy steels. The Charpy impact energy, the fracture toughness and tensile properties of these heats have been determined and the toughness results will be discussed in terms of measured inclusion sizes, volume fractions, spacings and resistance to void nucleation.