A novel and sensitive label-free aptasensor has been developed based on direct electrodeposition of gold nanoparticles (AuNPs) on NH2-reduced graphene oxide (rGo-NH2) modified electrode for the determination of adenosine triphosphate (ATP). The constructed AuNPs/rGo-NH2 nanocomposite not only has the merits of large specific surface area and good biocompatibility, but also has high conductivity and excellent electrochemical activity. These deposited AuNPs produced a strong electrochemical signal, which can be used as redox probes for the detection of ATP. The AuNPs/rGo-NH2 based-aptasensor is sensitive, selective and has a wide linear range from 10 pM to 100 nM, with the detection limit down to 10 pM. This sensing strategy will have potential applications in clinical diagnostics and biotechnology. (C) 2015 Elsevier Ltd. All rights reserved.