Young adult female mice were injected with lead acetate (d 0). Following injection, determinations were made of the percentages of radioactive iron (59Fe) uptake into the hemoglobin of erythrocytes produced by spleen. Control59Fe uptake percentage vacillated between 4.2 and 5.5 within the 7‐d period of observation. On d 4 following lead treatment, splenic percentages were dramatically reduced below those of the saline‐injected controls; by d 6 the splenic59Fe uptake of lead‐treated mice was comparable to that of controls. For rodents injected with cadmium chloride on d 0, the59Fe uptake values showed a statistically significant elevation by d 2, which was extended beyond that of the controls’ d 4 value. For those animals receiving both lead and cadmium (d 0), the uptake percentages paralleled those of the controls throughout the 7‐d period of observation. These data suggest that the inhibitory effect of lead on erythropoiesis of the spleen is blocked by a concurrent cadmium treatment. Results are interpreted in regard to a possible vulnerable target and competition for the target by lead and cadmium.