The present study examined the effect of DS exposure on median nerve development in rats during prenatal life. Pregnant female rats were divided into three groups: a control group, a saline group and a DS group. Offspring of these animals were divided into 2 subgroups: 4 weeks old and 20 weeks old. Nerve samples were taken from the right legs and evaluated using stereological techniques in terms of the axon number, axon cross-sectional area, and myelin thickness. No drug-dependent macroscopic abnormality was observed in the nerve. No differences were noted for axon number in the control, saline, and DS groups of the same age and gender No gender difference was found for axon number or axon area between the other matched groups. In conclusion, prenatal exposure to diclofenac sodium does not affect axon number in rats, but can alter the morphology of the male and female median nerve.