Abstract: Objective To study effects of soy isoflavones(SIFs) on estrous cycle and calcium,iron,and zinc contents in ovarian tissue of immature mice.Methods Postnatal day(PND) 21 imprinting control region(ICR) mice were treated with different doses of SIFs(50,100,and 200 mg/kg.BW.d)by gavage for 5 weeks.And then the estrous cycle was observed; the ovarian coefficient was calculated and the calcium,iron,and zinc contents in ovaries and serum of the mice were determined with atomic absorption spectrophotometer.Results The ovarian coefficient of the high-dose SIFs group(0.746±0.213 mg/g) was lower than that of the control group(1.135±0.468 mg/g)(P<0.05).There were no significant differences in the estrous cycle among all the groups(P>0.05).Compared with those of the control group, the ovarian calcium and zinc contents in all SIFs dose groups were decreased(P<0.05 for all) and the ovarian iron contents in midium- and high-dose SIFs groups were decreased(0.776±0.177 and 0.770±0.138 mg/g)(P<0.05 for all).The serum zinc content in midium- and high-dose SIFs groups were increased(3.570±0.697 and 4.954±1.448 μg/ml)(P<0.05).There were no significant differences in serum calcium and iron contents in the mice of all groups(P>0.05).Conclusion Soy isoflavones administered to immature mouse could affect ovarian calcium,iron,and zinc contents.