HIV infection is associated with considerable psychiatric, as well as medical, morbidity. Epidemiological studies indicate that patients who are infected with HIV are at an increased risk of having a psychiatric disorder compared with uninfected individuals. Knowledge of infection with HIV is associated with considerable psychological stress. Moreover, HIV infection produces direct and indirect brain injury leading to the development of psychiatric conditions. Conversely, the vulnerabilities and behaviours necessary for contracting HIV are associated with some psychiatric disorders, so that increasingly large numbers of patients with these disorders are becoming infected with the virus. Patients with psychiatric disorders are at higher risk than others in the general population of continuing high-risk HIV-related behaviour, and are less responsive to education.The psychiatric disorders that are most common among individuals who have HIV infection are substance abuse, mood, anxiety and cognitive disorders. Psychiatric disorders are an aspect of HIV infection that responds to appropriate treatment. Such treatment is based on careful evaluation and differential diagnosis of psychiatric symptoms. A variety of psychotherapeutic agents are available to the clinician to treat these disorders. These are best administered after the establishment of good doctor-patient rapport, and in tandem with ongoing education and supportive psychotherapy.