Acute myeloid leukemia (AML) is the most lethal hematopoietic cancer and one of the most common acute leukemia. The current standard treatment for AML has been used for 40 years, but only 50% overall survival is achieved. The poor therapeutic outcome could be explained by the highly heterogeneous nature of AML and the difficulty in drug selection especially for frail patients. This leads to an emerging shift towards personalized treatment. However, an obstacle for AML drug screening is their spontaneous apoptosis in ex vivo cultures. We hypothesized the bone marrow microenvironment mimicked by osteolineage cells encapsulated in extracellular matrix (ECM) would support the survival of primary AML cells, and the presence of 3D cancer microenvironment would provide more accurate screening results. Studies have shown that stromal cells and ECM provides a pro‐tumoral environment and chemoresistance to AML cells. Therefore, we aimed to develop a high‐throughput drug screening platform which consists of osteogenic differentiated (OD) mesenchymal stem cells that are encapsulated in collagen microspheres being co‐cultured with primary AML cells. Our laboratory has been developing a 3D microencapsulation platform using naturally occurring ECM to fabricate physiologically relevant and ECM‐based 3D microtissues. Our results showed that the viability of AML cells was around 20‐40% when being cultured alone but significantly higher (80%) when being co‐cultured with OD microspheres, which could be explained by the increase in GRO‐α, OPG and IGFBP2 levels detected in the collected conditioned medium. Further experiments are underway to demonstrate the application of the platform for drug screening purposes.