For the first time, composition-tunable, high-yield, RhPt flowerlike bimetallic nanocrystals were successfully synthesized through an aqueous solution approach. The electrocatalytic activity of these RhPt nanoalloys toward methanol oxidation was investigated and compared to the activity of commercial Pt black and commercial Ru50Pt50/C. The Rh Pt flowerlike bimetallic nanoallys have shown composition-dependent and superior catalytic properties relative to those of commercial Pt black and commercial Ru50Pt50/C. The peak current density and mass current value of Rh19Pt81 nanoalloys are 0.75 mA cm(-2) and 0.12 mA mu g(-1), respectively. For commercial Pt black, they are 0.48 mA cm(-2) and 0.074 mA mu g(-1), and for commercial Ru50Pt50/C, they are 0.28 mA cm(-2) and 0.10 mA mu g(-1). Moreover, the chronoamperometric measurements show that the Rh Pt flowerlike nanoalloys have excellent stability over commercial Pt black and commercial Ru50Pt50/C.