In vitro studies of cultured native acute myelogenous leukemia (AML) blasts and cell lines have contributed significantly to our present knowledge about the pathogenesis of AML. In the present article we review different techniques for preparation and in vitro culture of AML blasts. Well-characterized serum-free in vitro conditions can now be used in experimental studies of AML, and this makes comparisons between different studies easier. We also describe assays for characterization of AML progenitor subsets (i.e., suspension cultures, colony assays, long-term in vitro culture, xenotransplantation in immunocompromised mice), and we discuss the possible use of AML cell lines as experimental models in AML. Furthermore, clinical studies suggest that the in vitro growth characteristics of AML blasts assayed by short-term culture of the total native populations can be used as a predictor of prognosis after intensive chemotherapy. These in vitro assays may therefore be used for more accurate identification of prognostic parameters and thereby form a basis for the development of simplified laboratory techniques suitable for routine evaluation of patients undergoing risk-adapted therapy. However, it will be equally important to further evaluate the clinical relevance of assays for primitive AML progenitors, and to develop simplified methods that can be used to characterize these progenitor subsets in the routine clinical evaluation.