Iron retention in adult male rats given 3 g dried ground peas, immature and mature (Pisum sativum cv Dark-skin perfection) and leafless (Pisum sativum cv Filby), extrinsically labelled with 0.25 muCi 59Fe, was measured by whole-body counting. The Fe was less well absorbed (P less than 0.01) from the mature peas (0.251 (SE 0.021)) than from the immature (0.384 (SE 0.032] or leafless peas (0.344 (SE 0.026)). The availability of Fe from the leafless peas was compared with that of defatted soya-bean flour by the same technique. Significantly more Fe (P less than 0.005) was retained from the pea flour (0.471 (SE 0.013)) than from the soya-bean flour (0.377 (SE 0.022)). The effect of adding pea testa to bread (97.6 g/kg dry weight), as in the production of high-fibre white bread, on Fe availability was measured and compared with the availability of ferrous sulphate in young and adult male rats. There were no significant differences between the high-fibre and low-fibre breads in either age-group, although the older rats absorbed less Fe from all three sources. Retention from high-fibre bread, low-fibre bread and FeSO4 was as follows (mean with SE): young rats 0.452 (0.037), 0.475 (0.040) 0.541 (0.032); mature rats 0.363 (0.034), 0.366 (0.030), 0.471 (0.028). It was concluded that the addition of pea testa to white bread does not have detrimental effect on Fe availability. Immature and leafless peas appear to be a better source of available Fe than soya-bean flour, despite similar fibre levels, but with maturity the Fe in peas is rendered less available.