Cannabidiol (CBD) showed antiproliferative activity and induction of apoptosis in chronic myelogenous leukaemia cancer cells (K562 cells). A consolidated DARTS (Drug Affinity Response Target Stability) and t-LIP-MRM (targeted- Limited Proteolysis-Multiple Reaction Monitoring Mass spectrometry) platform was applied to unveil the interactome of CBD and to shed light on its mechanism of action. Both approaches point to the identification of DNA topoisomerase 2-alpha (TOP2A) as a major CBD target in K562 cells.