Identification of metabolic pathways that are dysregulated in acute myeloid leukaemia (AML) offers significant promise for the development of new therapeutic strategies. Heme is an essential metabolite with broad biological activity that is required and produced by all cells. In addition to its catalytic role as a cofactor in hemoproteins, heme also directly regulates signalling and gene expression. We and others have shown that heme biosynthesis enzymes are among the most downregulated genes during AML progression; and large-scale CRISPR screening studies have revealed that AML cells have an increased dependence on the expression of pathway components. We analysed heme biosynthesis in mouse models, AML cell lines and patient samples and found that common AML driver genes cause reduced heme production capacity in leukaemic cells. The low heme state in turn affects mitochondrial metabolism and drives altered gene expression patterns, in part via heme sensing transcription factors including BACH1. In proof-of concept experiments we demonstrate that low heme AML cells have increased sensitivity to inhibitors of the electron transport chain and drugs that induce ferroptosis. Using unbiased CRISPR screening methodologies we are now uncovering novel biochemical pathways that are synthetic lethal with heme metabolism. Altogether, our data points to a model where low heme biosynthesis promotes metabolic and transcriptional programs that are beneficial for self-renewal but also result in vulnerabilities that can be exploited for therapeutic benefit.