This study focuses on the relationship between some aspects of intra-erythrocytic sodium metabolism (intra-erythrocytic Na content, Na.Li-countertransport), blood pressure, and family history of hypertension, in a group of 84 randomly selected school children (45 males, 39 females). Na,Li-countertransport was significantly related to both systolic blood pressure (SBP) and diastolic blood pressure (DBP) only in boys at the univariate level, but both of these associations lost statistical significance after the possible confounding role of weight and height were taken into consideration. In both sexes, participants with a family history of hypertension had similar values of both intra-erythrocytic Na content and Na,Li-countertransport to participants with no family history.We conclude that family history of hypertension does not seem to play an important role in the determination of either intra-erythrocytic Na content or Na,Li-countertransport at this age. Although the positive association between Na,Li-countertransport and blood pressure observed in adult males is already present in childhood, this probably is still, at least in part, dependent upon body size