In this communication, electroless deposition of Prussian blue (PB) on the electrode promoted by Pt nanoparticles (Pt-nano) is proposed for detecting H2O2 with adjustable sensitivity. Pt-nano/carbon nanotubes hybrid was initially used to modify the working electrode, followed by immersing it into the Fe3+[Fe-III(CN)(6)] aqueous solution for electroless deposition of PB through a simple chemical reaction, which was catalyzed by Pt-nano. The amount of PB deposit was controllable through varying the deposition time or the Pt-nano amount on carbon nanotubes. Detection of H2O2 was successfully realized, sensitivity being dependent upon the amount of PB in the system. This work first demonstrates the feasibility of controlling the sensitivity of PB-based amperometric sensors through nanoparticles-assisted chemical deposition of PB, offering new insight into the development of electrochemical sensors using PB as the transducer. (c) 2009 Elsevier B.V. All rights reserved.