Fundamental and applied research on nanomaterials has opened many windows of opportunities. This review addresses recent advances on preparations and applications of nanomaterial-based voltammetric chemo- and biosensors, with particular emphases placed on carbon nanomaterials, metal nanoparticles and semiconductor nanomaterials. Select novel strategies for constructing nanomaterial-based chemo- and biosensors are discussed, and the employment of many new signal transduction methods in conjunction with the resultant sensors have been developed. Topics covered here focus on the preparation of electrochemical sensors and representative applications.