The values of erythrocyte protoporphyrin, ferritin and mean corpuscular volume (MCV) measurements in diagnosing iron deficiency anemia were investigated in 72 iron deficient and in 25 healthy control infants. Receiver operator curve, sensitivity and specificity of erythrocyte protoporphyrin, ferritin and mean corpuscular volume were compared between the study and control groups. In the study group mean corpuscular volume, hemoglobin and ferritin concentrations were significantly lower, and erythrocyte protoporphyrin was significantly higher when compared to the control group. In the iron deficient study group, erythrocyte protoporphyrin was the most sensitive test and ferritin was the most specific test, whereas ferritin was the most diagnostic test and mean corpuscular volume was the least diagnostic test. A significant correlation between erythrocyte protoporphyrin and hemoglobin values was determined. We conclude that erythrocyte protoporphyrin is a more sensitive but less specific test than ferritin, and it can be used as a first-line diagnostic test in the evaluation of iron deficiency and in diagnosing iron deficiency anemia in infants.