A study was carried out to determine the frequency of combined iron deficiency and beta-thalassaemia trait in a cohort of British Asian children to see whether the trait protects iron status. Of 470 consecutive children with red cell microcytosis, 77 had beta-thalassaemia trait and 26 (34%) of these also had evidence of iron deficiency. It was most common and profound in children under five years of age where the prevalence was 16 in 33 (48.5%). This suggests that iron deficiency is no less common in Asian children with beta-thalassaemia trait than in those without. It should not be presumed that the trait protects iron status or that the two are in any way mutually exclusive, at least in the early years.