Chemicals that bind to DNA have been used in the treatment of cancer since 1942 and remain as one of the most important groups of anticancer drugs. It has generally been assumed that these drugs display little DNA target specificity, a prevailing view which has had a major impact on drug development as well as on the models for the modes of action of these compounds. However, we have recently shown that anticancer DNA minor groove-binding drugs are likely to preferentially exert biological effects on a small subset of sequences in the genome. Studies have shown that these drugs selectively inhibited the assembly of intrinsically curved DNA segments into nucleosomes and destabilized nucleosomes that had been preformed on such segments. This drug inhibitory action is likely to be of biological importance in the action of these compounds since curved DNA segments are rare in the genome and are frequently found in control regions for transcription and replication. A detailed description of these genomic targets is critical for the understanding of the mechanism of action of these drugs and for optimization of their therapeutic activity. These studies may also be relevant to other DNA binding drugs and thus could have far reaching application in the fields of anticancer drug development, cancer chemotherapy and chemical-induced carcinogensis.