Recent trends in microprocessor design heavily rely on large register files with large I/O bandwidths for sustaining performance; a possible solution to relieve this bottleneck is the adoption of multiple register files. In this paper we show how the problem of assigning variables to multiple register banks can be reduced to that of a hypergraph coloring and, also, propose a technique to perform this coloring; this technique is applied to the problem of variable partitioning for rnultipltregister- file VLIW architectures.