The value of the study is determined by the growing number of elderly in the population and the prevalence of cognitive impairment among them. Identifying the latter in social support institutions is an important task. Meanwhile, by the current moment, the question of the use of short and relatively simple methods of examination of cognitive functioning by social workers remains undeveloped. This publication presents the comparative results of the survey of 65 elderly people in one of the gerontological centers of St. Petersburg using the MMSE tests and watch drawing test in combination with overall assessment of functioning of the subjects, according to the method of M. Lawton and E. Brody (1969). There was also conducted the examination of the same persons by doctors using a comprehensive CDR cognitive functioning assessment scale. The following three variants of the results of these surveys were identified: coincidence (21.5%), moderate (60.0%), and significant (18.5%) discrepancies. It was revealed that the initial assessment of cognitive functioning by social workers with the considered methods in many ways gives grounds for formation of the idea about the presence and depth of cognitive decline among the elderly people. At the same time, it is important to correctly assess the level of functioning of the subjects. It should be taken into account that the greatest accuracy in identifying such violations takes place at the pre-dementia stage.