The developing mesonephros contains the mesonephric duct, mesonephric tubules, and rete cells. In males, they differentiate into the epididymal duct, efferent tubules, and rete testis, respectively. These structures in females cease development and persist as the epoöphoron and rete ovarii. The morphology and function of the female reproductive organs are closely related to steroid hormones. Therefore, we examined the expression of steroid hormone receptors in the epoöphoron and rete ovarii to clarify whether these remnants can react to the steroid hormones in adult female mice. Serial paraffin sections of ovaries collected from adult C57BL/6 J mice were prepared. Androgen receptor (AR), estrogen receptor (ESR1), progesterone receptor (PR), Ad4BP as a marker for the rete ovarii, and Pax2 as a marker for the epoöphoron were detected by immunohistochemistry. Additionally, the rete ovarii and epoöphoron were reconstructed in Amira software from image data of the serial sections. The rete ovarii was positive for Ad4BP at the hilum of ovary, and Pax2 was detected in the epoöphoron within the adipose tissue around the ovary. Pax2 was also found in a part of epithelial cells of the rete ovarii. The Pax2 positive epithelial cells of the epoöphoron and rete ovarii were also positive for AR and ESR1. The PR expression was confirmed in neither the rete ovarii nor epoöphoron. Three-dimensional reconstruction confirmed a convoluting duct, which divided 3-4 branches extending toward the rete ovarii. The Pax2-positive epithelium of the rete ovarii also protruded to the epoöphoron. However, no contact between the rete ovarii and epoöphoron was found in almost all cases. The epithelium of mesonephric tubules, which have connected to the rete ovarii, is suggested to be partially stranded on the rete ovarii during the regression in the female mouse. These epithelial cells left in the postnatal rete ovarii probably retain the sensitivity for androgen and estrogen.