Cryptorchidism and testicular tumours are very common disorders in dogs genitalia. The aim of the present study was o obtain an overview of serum 17β-oestradiol, anti-Muellerian hormone (AMH) and testosterone levels in intact dogs compared to dogs with different testicular tumours and dogs with cryptorchidism. Testosterone, AMH and 17β-oestradiol concentrations were measured in peripheral and local spermatic venous blood in dogs with unilateral cryptorchidism (n=8), dogs with neoplastic testicular diseases (n=8) and in a control group of mature intact dogs (n=8). Results confirmed significantly higher concentrations of testosterone in local venous blood (control group: right testicle (RT) 46.23 ± 40.88 ng/ml and left testicle (LT) 50.76 ± 43.76 ng/ml; cryptorchid group: RT 23.91 ± 22.79 ng/ml and LT 10.52 ± 7.37 ng/ml; tumour group: RT 37.26 ± 25.26 ng/ml and LT 44.86 ± 19.03 ng/ml) (p<0.05) compared to their concentrations in peripheral blood (PB) in a control (4.92 ± 3.3 ng/ml) and in a cryptorchid group (0.89 ± 0.78 ng/ml), but not in the tumour group (11.37 ± 10.86 ng/ml). However, we have found increased level of testosterone in PB in the tumour group compared to its PB concentrations in the control or the cryptorchid group. Concentrations of AMH in PB observed in the cryptorchid group was 54.98 ± 30.07 μg/ml and in the control group was 6.49 ± 3.24 μg/ml (p<0.05). The same was observed in the case of local blood concentrations, which were significantly higher in the cryptorchid group (RT 51.92 ± 30.59 μg/ml; LT 46.33 ± 34.86 μg/ml) (p<0.05). We also observed high oestradiol concentrations in the cryptorchid group in both peripheral and local blood (PB: 30.86 ± 20.28 pg/ml; RT: 55.71 ± 34.7 pg/ml; LT: 78.99 ± 47.72 pg/ml), and even higher in the tumour group (PB: 52.46 ± 34.02 pg/ml; RT: 188.16 ± 132.67 pg/ml; LT: 297.14 ± 245.56 pg/ml). AMH has been shown to be a specific biomarker of gonadal tumours originated in Sertoli cells. It is also useful marker for confirmation of the existence of a functional cryptorchid testis. According to us, the scientific work dealing with a disorder of testicular descent in dogs, regarding the evaluation of sex hormones levels and the formation of the testes using modern diagnostic methods, significantly contribute to the clarification of some processes, leading to pathophysiological disturbances during this process.