AbstractDamage of salmon sperm double strand ss dsDNA in solution or immobilized on screen‐printed carbon electrode (SPCE) induced by incubation of DNA with the antineoplastic alkylating agent busulfan (BUS) at various conditions was detected for the first time by simple electrochemical methods. Chemical changes in DNA bases can be detected through the altered electroactivity of the DNA. Electrochemical voltammetric sensing of damage caused by BUS to dsDNA in solution was monitored by the appearance of peaks diagnostic of the oxidation of guanine and adenine. Moreover, crystal violet, which interacts with the DNA immobilized on SPCEs, was used as an effective electroactive indicator, in combination with cyclic voltammetry and differential pulse voltammetry techniques to monitor the cross‐links or damage to DNA. The interaction between BUS and DNA were determined by the changes in the voltammetric peak of crystal violet. The effects of various conditions upon the crystal violet signal were investigated.