© Cocuk Cerrahisi Dergisi. All rights reserved.Aim: The existence of androgen, estrogen and progesterone hormone receptors in the ureteropelvic junction (UPJ) has not been investigated previously. This study aims to investigate the expression of these 3 hormone receptors in UPJ region. Material and Methods: This prospectively designed study was done between January 2013 and January 2014. Biopsy specimens of the children operated due to UPJ obstruction were used. All specimens were obtained during the operation from obstruction area of UPJ (Group 1, n=12) and concurrently excised renal pelvic region (Group 2, n=9). The presence of androgen, estrogen and progesterone hormones receptors were investigated with avidin-biotin horseradish peroxidase technique in biopsy materials excised. Reactions were interpreted as positive, and negative based on the presence and absence of nuclear staining for each receptor. Results: Eight male and 4 female children with UPJ obstruction were operated during one-year period. The mean age was 2.3 years (1 month - 7 years). Progesterone hormone receptors were found to be negative in all specimens excised from obstructed UPJ region. Androgen (n=2), and estrogen (n=1) receptor positivities were detected in indicated number of biopsy specimens. In Group 2 progesterone, estrogen, and androgen positivities were found in renal pelvic biopsy specimens of 6, 2, and 8 cases, respectively. Conclusion: The urogenital system has a very rich network of sex hormone receptors and according to the analytical results of our immune histochemical the UPJ and adjacent pelvic region are target regions of these hormones. However, these results do not provide responses for the role of receptor-hormone effects on the area of UPJ obstruction and further studies are necessary for the clarification of this issue. This study is important in that it investigated androgen, estrogen and progesterone hormone receptors in the renal pelvis and the UPJ region, and demonstrated the presence of sex hormones in this region in children with hydronephrosis.