The paper proposes an input-output-waste (I-O-W) model as an extension of the input-output model to incorporate waste management (WM) aspects in national planning. The waste aspects have not been explicitly considered in the existing literature on input-output economics. It is visualized that in the economic structure the waste parameter has a significant role to play, and the I-O-W model will be a closer representation of the economy than that of conventional input-output models. Any unnecessary input to or any undesirable output from the system is considered as waste. The basic framework of an I-O-W model is presented, which consists of a technology matrix, a final-demand matrix, and a WM policy matrix. The resource balance has been established by treating the input to be equal to the sum of output and waste. The technological coefficients are interlinked by wastivity indices. The projections of a hypothetical economy consisting of one production sector and one WM sector have been determined for material resources and for different WM policies.