The objective of this study was to evaluate the testicular changes and detect the presence of Leishmania sp. in the testicles and semen of dogs with Visceral Leishmaniasis (VL). The animals were obtained from the Zoonoses Control Department of Teresina, PI, and taken to the kennel of the Agricultural Sciences Center of the Federal University of Piauí, where they remained were maintained for two months and subsequently euthanized for testicles removal. Semen samples were collected from 12 dogs, 06 positive and 06 negative for VL. The following diagnostic techniques readouts were assessed for the sampled animals: testosterone dosage, immunohistochemistry (IMH), histopathology of the slides containing the testicular material, and seminal evaluation by polymerase chain reaction (PCR). Testosterone values remained within the normal range for the canine specie and did not differ statistically among the experimental groups but displayed lower serum concentrations than those of the control group. All the testicular and semen samples from the dogs were negative for VL as determined by techniques IMH and PCR, respectively. The results of testicle histopathology revealed the presence of several lesions with statistical difference among the experimental groups. Parasitized dogs with VL have testicular lesions that may compromise the reproductive efficiency of these animals.