The mean values of the Epo level and the Hb F content in the two groups of beta-thal int seem to be positively related, but an accurate analysis of single cases indicates (Tab. 2) that the Epo level and Hb F content are unrelated: subjects showing a low content of Hb F and an high level of Epo as well as subjects showing an high content of Hb F and a low level of Epo were frequently observed. This observation is reinforced by the analysis of groups of subjects in which the severity of anemia is similar. Within the group of evident beta tal int patients (the only adapt for this analysis) subjects showing an Hb F level higher or lower than 40% [5,6] were selected. As illustrated in Fig. 2 and Tab. 3, subjects having a very similar Epo level and Hb content fall in both classes of Hb F content, indicating that Hb F content and Epo level are not related.