The power dissipated by system-level buses is the largest contribution to the global power of complex VLSI circuits. Therefore, the minimization of the switching activity at the I O interfaces can provide signi cant savings on the overall power budget. This paper presents innovative encoding techniques suitable for minimizing the switching activity of system-level address buses. In particular, the schemes illustrated here target the reduction of the average number of bus line transitions per clock cycle. Experimental results, conducted on address streams generated by a real microprocessor, have demonstrated the e ectiveness of the proposed methods.