Cisplatin, a DNA-damaging agent, is one of the most widely used anticancer drugs. As with all members of this class of chemotherapeutic compounds, the clinical success of cisplatin is compromised if tumor cells become resistant by various mechanisms, including enhanced DNA repair. In addition to its role in resistance, DNA repair has been linked to the cytotoxic mechanism of cisplatin. DNA damaged by the drug has proved to be a valuable tool for exploring the details of the nucleotide excision repair pathway.