Overall 370 mentally retarded persons (aged 15 to 35 years) staying at the specialized institutions of the RSFSR Ministry of Social Welfare were examined. The degree of the intellectual defect, concomitant psychopathological disorders, correlations between the degree of the intellectual defect and the ability for mastering labour and social skills, the conditions of living and training of the patients were accepted as criteria for social and labour prediction. Statistically significant differences were established in the values of integrative mark estimations of patients with pronounced debility, of those with mild, medium and profound imbecility. Significant correlations were revealed between the degree of mental retardation, on the one hand, and the level of mastering labour skills and social experience, on the other one. In the patients with pronounced debility, the psychopathlike syndrome was among concomitant psychopathological disorders producing a significant effect on social and labour prognosis. The relationship was established between the magnitude of the integrative assessment of the degree of the intellectual defect and realization of potential capacities of mentally retarded persons.