The study assessed the relative contribution of infections and iron deficiency to anaemia in Nigerian mothers and their children. Sixty-one mother-child pairs were recruited. The mean ages of mothers and children were 31.05 +/- 9.35 years and 30.85 +/- 16.70 months, respectively. Dietary iron intake was used as proxy for iron status while anaemia was diagnosed by whole blood haemoglobin concentration < 120 g/L in mothers and < 110 g/l in the children. A structured questionnaire was used to collect information on the exposure of the mothers and their children to infections. Approximately 53% of mothers and 56% of children had abnormal haemoglobin concentrations indicative of anaemia. Also, 41% of the mothers and 37% of the children had dietary iron intakes below the recommended dietary allowance. In the preceding 6 months of the study, about 50% of the mothers, and 65% of the children in the preceding month, were ill. Febrile illness accounted for 70% and 30% of the illness in mothers and children, respectively. There was significant correlation between mothers' and children's dietary iron intake and blood haemoglobin concentration. In conclusion, iron deficiency and infections were equally important aetiological factors in the anaemia recorded in the subjects of this study.