Despite major advances in our knowledge of iron nutrition in infancy, iron deficiency remains a significant problem in the UK. The precise size of the problem is unknown, but there appears to be a higher risk amongst certain ethnic groups. Nutritional iron deficiency appears after the age of 6 months and is undoubtedly linked to inappropriate feeding practice. High bioavailability of iron in weaning foods is of paramount importance in preventing iron deficiency, whether using family foods or commercially available products, and further information about different foods and diets is needed. The long-term detrimental effect on mental development makes prevention of iron deficiency a high priority public health objective for the 1990s.