Here, via a thorough and extensive comparison of the anti‐leukaemic potential of a panel of FLT3 inhibitors that have either been FDA approved (midostaurin and gilteritinib) or that are in late‐stage clinical development (crenolanib, quizartinib and sorafenib), we show that all FLT3 inhibitors, regardless of their broad or narrow range of targeted activity, are potent inhibitors of growth of mutant CBL‐positive leukaemia, with some, like crenolanib, gilteritinib and midostaurin, showing more activity than others against primary mutant CBL‐positive leukaemia. This evidence concerns the gene FLT3 and leukemia.