Mutant isocitrate dehydrogenases (IDHs) produce R-2-hydroxyglutarate (R-2HG), which inhibits the growth of most acute myeloid leukemia (AML) cells. Here, we showed that necroptosis, a form of programmed cell death, contributed to the antileukemia activity of R-2HG. Mechanistically, R-2HG competitively inhibited the activity of lysine demethylase 2B (KDM2B), an α-ketoglutarate-dependent dioxygenase. KDM2B inhibition increased histone 3 lysine 4 trimethylation levels and promoted the expression of receptor-interacting protein kinase 1 (RIPK1), which consequently caused necroptosis in AML cells. The expression of RIPK3 was silenced because of DNA methylation in IDH-mutant (mIDH) AML cells, resulting in R-2HG resistance. Decitabine up-regulated RIPK3 expression and repaired endogenous R-2HG-induced necroptosis pathway in mIDH AML cells. Together, R-2HG induced RIPK1-dependent necroptosis via KDM2B inhibition in AML cells. The loss of RIPK3 protected mIDH AML cells from necroptosis. Restoring RIPK3 expression to exert R-2HG's intrinsic antileukemia effect will be a potential therapeutic strategy in patients with AML.