Objectives. To study the clinical manifestations of neuroleptic-associated hyperprolactinemia (NAH) and its influences on sexual functions in patients with mental disorders and prolonged treatment with neuroleptics. Materials and methods. A total of 244 patients were investigated – 140 women and 104 men – with mental disorders and receiving treatment with neuroleptics. Blood prolactin and bioactive prolactin levels were estimated in all patients, these assays in some patients being accompanied by determination of gonadotropins, sex hormones, and sex steroid-binding globulin. Side effects of neuroleptics were assessed using the UKU Side Effects Rating Scale. Impairments to sexual functions were assessed using the Psychotropic-Related Sexual Dysfunction Questionnaire. Results and conclusions. Asymptomatic NAH was detected in 16% of women and 37% of men. In women, NAH led to impairments in the menstrual cycle – oligo- or amenorrhea – and galactorrhea. NAH was accompanied by sexual impairments in both in both men and women. In patients of both genders, NAH was associated with weakening of libido and deterioration of quality of life due to sexual impairment. In addition, women with NAH had delayed onset of orgasm and vaginal dryness during sexual intercourse. In men, NAH was also associated with erectile dysfunction. In contrast to tumor-related and idiopathic hyperprolactinemia, NAH was not accompanied by increases in body weight and the development of obesity, or the development of hypogonadism in patients of either gender.