Antisense oligodeoxynucleotides (ODNs) have great promise for therapy. Oligomers labeled with gamma-emitting radioelements have great promise for diagnosis. These radiolabeled oligomers can be used to identify the presence of a particular messenger RNA through simple external detection of radioactivity by means of scintigraphy. This review evaluates the progress in the development of antisense oligodeoxynucleotides for non-invasive imaging of chemoresistance. As nominated by H.N. Wagner at the final session of Nuclear Medicine congress in Denver, the deoxyribonucleic acid is "the molecule of the millennium".