Ethical and moral issues surround the practice of animal euthanasia, which often damages the veterinarian’s mental health, leading to psychological problems and even suicide. This study aimed to evaluate veterinarians’ perceptions about euthanasia and the possible implications of the practice for their mental health and seek to identify gaps in the training of these professionals. Data collection occurred by applying an online questionnaire sent to veterinarians working in the Brazilian territory. Among the 243 participants, 78% said they did not have classes that broadly addressed the practice of animal euthanasia and dysthanasia during undergraduate disciplines; in addition, 71% claimed that they did not address subjects such as medical ethics, psychology, mental health, and verbal communication. The vast majority (90%) considered not trained to deal with patient death, and 67% have already questioned whether the procedure was the best alternative. The presence of sadness after performing euthanasia was frequent among participants. Small animal clinicians were more susceptible to the presence of this feeling when compared to a veterinarian from other areas. Most veterinarians (86%) believed that the practice of animal euthanasia poses risks to the performer’s mental health, and 89% claimed that it influences their mental health. 17% of the participants were using controlled medications during the research period. So, given these findings, it is evident that animal euthanasia negatively affects the mental health of those who perform it. Measures are needed to minimize the impacts arising from the practice, aiming to improve this population’s health and well-being.