The aim of this study was to assess the iron balance status in the group of 151 male regular blood donors with normal hemoglobin (Hb) and hematocrit (Ht) level who had given over 10 donations of the whole blood with the frequency of 4-6 units per year. We though to determine the prevalence of iron deficiency in this group of donors and its relationship with the cumulative number of previously given blood, as well as to compare the sensitivity of serum ferritin (FRT) with serum soluble transferrin receptor (sTfR) level in detecting tissular iron stores depletion in donors with normal blood count. The control group comprised 50 age-matched first-time donors. For each donor we determined the blood count, serum iron level, total iron binding capacity (TIBC), transferrin saturation, serum transferrin (TRF), FRT and sTfR level. We determined also serum erythropoietin (EPO) level. In all first-time donors iron metabolism parameters and EPO level were normal. In regular donors following abnormalities were noted: FRT level was below 20 micrograms/l in 75 (49.7%), sTfR was increased in 28 (18.5%) of donors. In the majority of donors with an increase of sTfR level FRT level was decreased (22 out of 28, 78.6%), but sTfR concentration was elevated only in a small proportion of donors with a decrease of FRT level (22 out of 75, 29.3%). When compared mean values between two groups of donors, following differences were found: TIBC, TRF, sTfR and EPO were significantly higher, and MCV, FRT and TS were significantly lower in regular donors than in control ones. We did not found a relationship between the cumulative number of previous donations and the degree of iron depletion; a positive correlation of this number with FRT level is to be explained by a relationship between FRT level and the donors' age. In conclusion we found a high incidence of iron depletion in regular whole blood donors with normal blood count. It is then advisable to regularly check the iron metabolism status in those donors in order to prevent them from keeping on giving blood until the restoration of iron balance.