Abstract In each of two experiments, adult, male Sprague-Dawley rats were deprived of copper and were subjected to the chronic stress of close confinement. A 2 × 2 factorial design was used because both copper deficiency and stress have been implicated in the regulation of blood pressure and are implicated in a major consequence of human hypertension— ischemic heart disease. Copper deficiency was verified by a decrease in copper in several organs. Both copper deficiency and stress increased blood pressure; results were independent. Sodium in heart was increased by deficiency in both experiments, but was increased in brain in only the second experiment. The combination of stress and deficiency produced an increase in mortality in one of two experiments. A decrease in cholesterol in plasma due to stress is consistent with earlier data from rats but is in contrast to data from humans. Both stress and copper deficiency produce potentially adverse changes in cardiovascular physiology and the chemistry of brain, heart and other organs. These results may be germane to humans because stress is frequent and some diets are low in copper.