There is a huge progress in the development of electrochemical DNA-based biosensors. DNA-based biosensor can test the reactivity of surface attached DNA. Preparation of these biosensors is typically based on the concept of chemically modified electrodes. As affinity biosensors, they combine the recognition ability of DNA as a biocomponent and the power of electroanalytical methods. Investigation and screening of binding interactions of double stranded (ds) DNA with low molecular weight compounds such as drugs and potential risk chemicals together with damage to DNA are of interest for pharmaceutical and medical chemists as well as in environmental and food research. Modern construction utilizing nanomaterials and applications of the biosensors are reviewed.