BACKGROUND: Low educational level is common among Brazilian elderly and can affect the results of usual cognitive testing. OBJECTIVE: To evaluate the impact of age, and educational level on MMSE performance, in a community-dwelling sample of elderly individuals. METHODS: A community sample was obtained, based on the public health program "BH Vida", Belo Horizonte, Brazil. Home visits were done between August 2001 and June 2002. A Portuguese version of the MMSE was administered to the elderly during home visits. RESULTS: Our sample was composed of 176 individuals, aged 65-97 years old (median = 71). Educational level ranged from no formal education to 13 years of education (median = 3). The MMSE scores ranged from 1 to 30 (median = 23). Both age and educational level had a statistically significant influence in MMSE (p < 0.001 e p < 0.0001, respectively). CONCLUSION: Even in the low educational level elderly, length of formal education was a factor significant influencing MMSE score. Increasing age predicted lower total MMSE score.