1. Four Negro patients and their families previously reported in 1949 as examples of Mediterranean anemia were re-evaluated with regard to hemoglobin composition. The data have been presented.
2. Mediterranean anemia was confirmed in one entire family and in the index case of another family.
3. Two entire families and one member of another family were found to possess hemoglobin C.
4. Differential diagnostic points of Mediterranean anemia and hemoglobin C disease are presented.