Copper is both an essential and a toxic element for man and other animals. A deterministic compartment transfer model was developed that can be executed on a personal computer. This model appears to be equally applicable to rats and cows which exhibit grossly different copper metabolism patterns. The model incorporates compartment limits analogous to those found in normal animals. Simulations gave good agreement with published data. This model should be useful for planning experimental investigations into the differences in copper metabolism between species.