Animal-assisted therapy is a structured, planned and goal-oriented therapeutic intervention that involves interactions between the patient and the animal, with the therapist and the animal's handler. The therapeutic potential of animals was first recognized in the late 1800s by Florence Nightingale, who noted that small pets helped reduce anxiety in children and adults. Later, the therapeutic potential of animals was also recognized by Sigmund Freud, Boris Levinson, Samuel and Elizabeth O'Leary Corson, and the most significant breakthrough was achieved by the Delta Society, which established valid programs and guidelines for the application of therapy with the help of animals. Numerous studies demonstrate the benefits of animal-assisted therapy on objective parameters such as vital signs, hemodynamic stability, blood hormone levels, and physical activity. The psychological benefits of animal-assisted therapy have also been proven, such as increasing the feeling of satisfaction and happiness, reducing the feeling of loneliness, and increasing the quality of life. Based on the research results reviewed in this paper, animal-assisted therapy is effective in reducing symptoms of mental illness and leads to improved global functioning, reduced violent behavior, and improved self-esteem. The results of the research included in this paper with the aim of proving the effectiveness of animal-assisted therapy in the treatment of patients with schizophrenia prove that it is effective in reducing psychopathological symptoms, in combination with standard forms of treatment. According to the results of the research included in the work, animal-assisted therapy is effective in reducing symptoms in patients with depression.