IN THIS PAPER WE CONSTRUCT a computable general equilibrium model, calibrate it to selected data for the American economy, and use it to explore the efficacy of the seigniorage tax associated with various monetary arrangements. We find that the key feature of any monetary-tax arrangement is its equilibrium after-tax real return schedule on liquid assets held by the households. We also find that considerable seigniorage, which we define to be the diSerence between government expenditures other than interest paid on government debt and taxes collected, can be large. We find that the seigniorage tax is a poor one relative to a tax on labor income. ln particular, we find that if the after-tax real return on saving deposits is -5 percent, as it was on average in the 1974-1978 period, welfare is one-half percent of consumption lower than it would be if the after-tax real return were zero, as it approximately was in both the 1964-1968 and 19841988 periods. The work builds on that of A. imrohoroglu (1990), who finds that for worlds in which non-interest-bearing nominal assets are the only liquid assets, the cost of constant inflation is far greater than the area under the empirical demand for money relation. With such arrangements, the after-tax real return is the negative of the inflation rate. The key feature of her model is that agents hold money in order to smooth consumption in the face of idiosyncratic income variability for which there