To analyze the cognitive ability of elderly people assisted by the Family Health Strategy (FHS) in a northeastern Brazilian city, a cross-sectional, analytical study was conducted with 406 elderly assisted by the FHS in Mossoro-RN, Brazil, from March to May 2014. The data were collected through two validated questionnaires. For the data analysis, the Alpha Cronbach's, Kruskal-Wallis test, chi-square and Pearson correlation statistical tests were applied. There was a predominance of women (67.98%) in the survey. Among the respondents, 50% had an index of up to 27 points in Pfeffer Instrument, identifying greater degree of dependence in performing instrumental daily activities related to mobility in the community (39.7%) and financial management (57.1%). On Mini-Mental State Examination (MMSE), 75% of seniors had an index above 27 points, with the scores classification as standard (50.99%), mild (25.12%), moderate (22.66%) and severe (1.23%). Although changes have been identified in cognitive performance and independence of elderly people in some areas, these difficulties do not completely affect the lives and daily activities of the elderly.