Abstract
With integrated luminosity 10.5 fb^-1 data acquired at Belle, we have studied two charmless hadronic B decay modes, B^0 -> rho pi and B^0 -> rho K. In this study, we have measured the branching fraction of B^0 -> rho pi to be 20.2+8.3-6.6 x 10^-6 and because the significance of the B^0 -> rho K channel is still small, we only give the upper limit of this mode to be < 23.6 x 10^-6 at 90% confidence level.