The local renin-angiotensin system (RAS) in bone marrow is probably involved in the control of hematopoiesis. Earlier observations suggest the relationship between the frequency of sodium and potassium concentration changes in urine and bone marrow recovery after chemotherapy. The purpose of this study was to prove the relationship between sodium and potassium excretion changes in urine and granulocyte counts in peripheral blood after autologous bone marrow and peripheral blood stem cell transplantation. The correlation between amplitude maximum FFmax of F=d[Na]/d[K], where d[Na] and d[K] are changes of sodium and potassium excretions in 24 h, and granulocytes, recorded k days later, was found in 12 patients with autologous bone marrow transplantation (BMT) and/or PBSCT. In patients with successful engraftment, k ranged from 4 to 7 days. In the patient with unsuccessful BMT, k was 12 days. The results imply the interaction between systemic and bone marrow RAS.