An assay was developed for the 1,N2-propanoguanine adducts generated in DNA by reaction with biologically relevant alpha,beta-unsaturated aldehydes. The analysis takes advantage of the electrochemical activity of the adducts released as modified bases by quantitative acidic hydrolysis of the DNA. The detection limit of the method is around 1 pmol in DNA. Emphasis was placed on the detection of the derivatives of 4-hydroxynonenal (a final product of lipid peroxidation) and hexenal. The adducts were detected in calf thymus DNA incubated with these two unsaturated aldehydes. The 4-hydroxynonenal-1,N2-propanoguanine derivatives were not observed in DNA extracted from young rat kidneys or liver. The technique was shown to be also applicable to a series of alpha,beta-unsaturated aldehydes-1,N2-propanoguanine adducts which were found to be electrochemically active at relatively low potential and efficiently separated by reverse-phase HPLC.