Abstract: Nodular cast iron having favorable mechanical properties, in particular a high impact strength at low temperatures, comprising: from 3.0 to 4.0% of carbon; from 1.5 to 2.3% of silicon; less than 0.3% of manganese; not more than 0.03% of phosphorus; less than 0.10% of chromium; from 0.02 to 0.06% of magnesium; and from 0.0015 to 0.0150 weight % of bismuth with the balance consisting of iron and inevitable impurities and the CE (carbon equivalent) value being from 3.9 to 4.6%. This material is characterized by a low silicon content. Adding from 0.5 to 2.0% of nickel thereto improves its tensile strength and yield strength. Preferably, from 0.005 to 0.03% of bismuth is added to this nodular cast iron in molten state so as to produce more than 300 graphite nodules per mm.sup.2. The remaining bismuth content is preferably from 0.0015 to 0.015%, more preferably from 0.0015 to 0.004%.