Because high barium concentrations (2–10 ppm) in human drinking water have been reported to be associated with elevated cardiovascular mortality, hypertension and other cardiovascular effects were sought in rats chronically exposed for 1–16 mo to drinking water containing 1, 10, or 100 ppm barium. From weaning, female Long‐Evans rats were kept in a “low contamination” environment and fed a diet low in trace metals. Their drinking water was deionized, fortified with 5 essential trace metals, and either 0,1, 10, or 100 ppm barium was added. Indirect systolic pressure of unanesthetized rats was measured in triplicate at 1, 2, 4, 8, 12, and 16 mo.