Early diagnosis and treatment in the predementia stage of Alzheimer's disease, i.e. in amnestic MCI (aMCI) may improve patient quality of life and promote slowing of conversion to dementia. The purpose of the study was to analyze the effectiveness and long-term prognosis of the course of cerebrolysin therapy in aMCI patients. Twenty elderly aMCI patients were included in the study and treated with a 20-day course of therapy with daily intravenous infusions of 30 mL cerebrolysin. Cognitive functions were assessed by the battery of neuropsychological scales and tests: MMSE, MoCA-test, МDRS, the Boston naming test, the Clock Drawing Test, Frontal Assessment Battery, the test “10 words”, the Digit Repetition Test. The level of the auto-antibodies to a short peptide fragment of the neurotrophins P75 receptor has been investigated by ELISA in the patient blood serum 3 times per 6 months (0, 10 and 26 weeks). Analysis of the data showed a statistically significant improvement in psychometric tests at the therapy end and also at 10 and 26 weeks of the study. Long-term therapeutic effect (5 months) proved to be significantly correlating with the following parameters: patient's age older than 70 years, basic indices of the MoCA-test and the test “memory” of the dementia Matisse scale. The decline serum level of autoantibodies to the fragment 155–164 receptor of neurotrophins P75 also provided to be an indicator of the long-term effectiveness of the therapy. These results could determine those aMCI patients who could have positive long-term therapeutic effect following cerebrolysin treatment.