We use optical tweezers and atomic force microscopy to investigate the potential of rare earth elements to be used as anticancer agents in the development of new chemotherapeutic drugs by characterizing the binding of three rare earths (ytterbium, neodymium, and erbium) to double-stranded DNA, which is one of the main targets for these drugs inside cells. The three elements presented a significant interaction with the biopolymer in buffers of physiological relevance, typically binding with very high equilibrium association constants (10