The development of biosensors and bioassays has focused recently on small, easy to use in a decentralized and portable manner and low-cost analytical devices for sensing and quantitative determination of biomarkers. Biosensors provide numerous advantages over other analytical techniques, including high selectivity and sensitivity, portability, miniaturization and possibility of on-site monitoring. Immunosensors were heavily used during the last decades, since they combine the specificity of the immune reaction between antibody and its specific antigen with the sensitivity provided by the detection platform. More recently, aptamers started to be used for the design of biosensors due to their improved characteristic compared to the antibody-based sensors. In this chapter an overview of the latest trends in electrochemical sensors design for diagnosis purposes of several diseases, including cancer, cardiovascular and neurological disorders, is presented.