Methylprednisolone has been reported to be produce hypertension in the rat but to have no effect on blood pressure in the dog. In this study, methylprednisolone infused to conscious sheep for up to 10 days at either 20 micrograms/kg/hr or 100 micrograms/kg/hr, failed to induce a hypertensive response. Metabolic effects characteristic of glucocorticoid activity, such as increased water intake and urine volume, were observed in all animals. No consistent decrease in plasma potassium concentration was observed with either rate of infusion, indicating a lack of in-vivo mineralocorticoid activity. In the conscious sheep, like the dog, methylprednisolone exhibits only glucocorticoid activity and does not increase blood pressure.