Despite the advanced understanding of disease mechanisms, the current therapeutic regimens fail to cure most patients with acute myeloid leukemia (AML). In the present study, we address the role of protein synthesis control in AML leukemia stem cell (LSC) function and leukemia propagation. We apply a murine model of mixed-lineage leukemia-rearranged AML to demonstrate that LSCs synthesize more proteins per hour compared with the bulk of leukemia. Using a genetic model that permits inducible and graded regulation of ribosomal subunit joining, we show that defective ribosome assembly leads to a significant survival advantage by selectively eradicating LSCs but not normal hematopoietic stem and progenitor cells. Finally, transcriptomic and proteomic analyses identify a rare subset of LSCs with immature stem cell signature and high ribosome content that underlies the resistance to defective ribosome assembly. Collectively, our study unveils a critical requirement of high protein synthesis rate for LSC function, highlighting ribosome assembly as a therapeutic target in AML.