To study the effect of exercise and protein intake during pregnancy on maternal and fetal zinc status in the rat, one hundred and seventy-nine pregnant Sprague-Dawley rats were divided into four groups; sedentary-standard protein diet, sedentary-high protein diet, exercising-standard protein diet and exercising-high protein diet. The standard protein diet contained 7.22% protein, while the high protein diet contained 24.77% protein; all other nutrients were supplied in amounts required for normal parturition of the laboratory rat. After acclimatization, the exercising dams, regardless of diet, were made to swim continuously for one and one-half hours/day until sacrifice. The four major groups were further subdivided into 28 groups, designated by three-day intervals according to gestational day--days 3, 6, 9, 12, 15, 18, and 21. Uterine tissues were retained for zinc content analysis; fetal and placental tissues were separated from uterine tissue for days 15 through 21 only. The concentration of uterine zinc was affected solely by gestation; absolute placental tissue zinc values were lowest in the sedentary-high and exercising-low protein groups, while the exercising-high protein group possessed the greatest zinc value. No significant difference was detected in fetal zinc concentrations. Fetal tissue from exercising dams weighed significantly less (p<0.05) than fetal tissue from the sedentary dams; and sedentary-high protein dams produced significantly more (p<0.05) fetuses than the exercising-high protein dams. Both protein intake and exercising during pregnancy significantly affect normal parturition and zinc metabolism in the rat. / M.S.