Abstract: Objective To examine effects of bisphenol A(BPA) on the development of ovary in immature rats.Methods Totally 48 Wistar male rats(4 weeks old) were randomly divided into a vehicle(olive oil) control and 3 different dosage BPA(10,40,and 160 mg/kg) treatment groups.All rats were treated by intraperitoneal injection one time a day for 8 days.The rats were sacrificed after the last weighing.Ovarian wet weight and ovarian/body weight ratio were examined.The contents of estrogen and progesterone in serum were detected.The numbers of ovarian follicle at different development stage were counted by serial section.Results Compared with the control group(0.71±0.126),the ovarian/body weight ratios were reduced in 40 and 160 mg/kg groups(0.45±0.109,0.36±0.196)(P<0.01).The contents of estrogen in serum showed no significant change compared with the control group(P>0.05),but the contents of progesterone in 40 and 160 mg/kg groups(10.54 nmol/L,12.93 nmol/L) changed significantly compared with those of the control group(43.65 nmol/L)(P<0.01).In BPA treatment groups,primordial/secondary follicles were significantly lower and atresic follicles were significantly higher in 40 and 160 mg/kg groups(P<0.01).Conclusion The development of ovary could be depressed by BPA in immature rats.One of the mechanisms may be the increase of follicular atresia induced by BPA.