The advent of continuous human leukemia–lymphoma cell lines as a rich resource of abundant, accessible and manipulable living cells has contributed significantly to a better understanding of the pathophysiology of hematopoietic tumors. We describe the establishment of the new continuous leukemia cell line MUTZ-8 from a patient with acute myeloid leukemia (AML): MUTZ-8 was derived from the peripheral blood of a 63-year-old woman with AML M4 (25 years after onset of myelodysplastic syndromes, MDS). DNA fingerprinting confirmed authenticity and derivation of the cell line. The immunoprofiling as determined by flow cytometry showed that MUTZ-8 is positive mainly for myeloid but also some monocytic and megakaryocytic markers, whereas it is negative for T cell, B cell and erythroid markers. The cell line is constitutively cytokine-dependent, proliferation requiring externally added cytokines. The cytokine response profiles showed a two- to 10-fold growth stimulation of the cells by various cytokines, whereas other cytokines led to growth inhibition. Cytogenetic analysis confirmed the common clonal derivation of the cell line and the malignant clone predominating at the times of sampling. MUTZ-8 displays a deletion of the 5q31 AML/MDS region effected by a non-reciprocal translocation, t(5;11)(q21;q10). The scientific utility of MUTZ-8 lies (1) in its cluster of pathognomonic cytogenetic alterations including a 5q31 breakpoint and (2) in its absolute cytokine dependency and proliferative response to various cytokines.