Following the initial success of imatinib as frontline therapy for chronic myeloid leukemia (CML), several second-generation therapeutics have been developed with increased potency and the ability to inhibit the majority of imatinib-resistant mutations. Here, we review the current knowledge about the target specificity of the two new inhibitors nilotinib and dasatinib in comparison to imatinib, including the recent large-scale chemical proteomics screens.