Local renin-angiotensin system (RAS) may affect leukaemic cell production within the bone marrow microenvironment. Angiotensin-converting enzyme (ACE), renin, and angiotensin could influence leukaemogenesis. In this study, mRNA expressions of the major RAS components (ACE, renin, and angiotensinogen) in K562 human erythroleukaemia cell line have been searched by Real Time quantitative polymerase chain reaction. K562 blasts are multipotential, haematopoietic malignant cells that spontaneously differentiate into recognisable progenitors of the erythrocyte, granulocyte and monocytic series. We observed significant expressions of ACE, renin, and angiotensinogen in K562 leukaemic blast cells. Therefore, K562 human erythroleukaemia cell line may serve as an in vitro model to elucidate the role of RAS in leukaemia and to test the effects of RAS-affecting drugs on leukaemic cellular proliferation.