Aim: To evaluate the biodistribution of 99mTc-RBC in an animal model of ferropenic anemia.Materials and methods: We used rats which were fed with different iron contents diets: group A (severeanemia, 6.5 ppm), group B (moderate anemia, 18 ppm) and group C (control, 100 ppm). We performed the in vivo labeling of RBC and evaluated the labeling efficiency and the biodistribution at 30 minutes and 24 hours in blood, liver, spleen, gastrointestinal tract, kidneys, heart and lungs. The results were expressed as activity concentration percentage (CA%).Results: In all groups the labeling efficiency was higher than 98%. We observed an increase of CA% in spleen at 24 hours in the group A, followed by a decrease of CA% in blood. This could be a consequence of an increase of splenic uptake of RBC. An increase in CA% in kidney was obtained at 24 hours for all the groups. Conclusion: An alteration in the RBC biodistribution is observed in an animal model of ferropenic anemia.