The aim of this study was to determine the serum anti-Müllerian hormone (AMH levels) in a group of boys with cryptorchidism before and 1 year after surgery. Additionally, the effect of orchiopexy, based on the testicular position and morphology, was evaluated. Fifty boys who were 1-4 years old (median, 2.4 years) with unilateral cryptorchidism were evaluated before and 1 year after they underwent orchiopexy. Prior to the procedure, all of the patients had undergone karyotyping to exclude chromosomal abnormalities. Blood samples were collected while obtaining blood for standard laboratory tests routinely performed just before and 12 months after surgery. Twelve months after the orchiopexy, in most cases surgically treated testes were in the middle or lower pole of the scrotum. The descended glands were of comparable size and density in comparison with the testes on the opposite side. In the treated children, serum AMH levels measured at 12 months after orchiopexy were similar to preoperative basal levels. The authors found that AMH levels in children with unilateral undescended testes do not change significantly 1 year after surgical procedure. We still do not have trustworthy factors to predict fertility in children affected with cryptorchidism. We observed an upward trend in AMH concentration 1 year after orchiopexy, but it was statistically insignificant. Therefore, we plan further measurements of AMH in boys after orchiopexy to assess the influence of this procedure on gonadal function.