The effect of consumption of certain iron compounds on liver iron deposition was studied in rats, in each case at 4 dietary iron levels ranging from 70 to 206 mg/100 g diet. In one of two series the basic diet was maize porridge meal, and in the other, a semisynthetic 'balanced' diet was fed. The siderogenicity of the iron compounds, when fed with maize porridge meal, was found to be in the following order: ferrous chloride> pulverised steel> pulverised cast iron>ferric chloride>ferric citrate=ferric lactate> ferric oxide. The relatively high siderotic effect of cast iron was reduced considerably when fed together with a semisynthetic 'balanced' diet. It was concluded that the presence of free iron particles in food, as well as the conditions prevailing in the gut as a result of consumption of a predominantly maize diet, are important contributing factors in the development of siderosis in the rat and most probably also in Blacks.S. A fr. Med. J., 48, 505 (1974)