Objectives: To present the methods and baseline characteristics of the Pietà study, a population-based survey investigating successful brain aging in the oldest-old. Method:The study was conducted in Caeté (MG), Brazil. In 2007, 1,251 individuals aged 75+ years were living in the city and were invited to participate. Participants responded to a general health questionnaire and were submitted to clinical, neurological, cognitive, psychiatric and functional evaluations. A subgroup was submitted to neuropsychological testing, blood tests and magnetic resonance of the skull. Individuals were classified as having cognitive impairment-no dementia, dementia, parkinsonism, psychiatric disorders or successful brain aging. Results: We evaluated 639 individuals (51.1% of the target population; 64% women), aged 81.4±5.2 years and with 2.7±2.6 years of schooling. Almost 30% of the elderly were illiterates and 82.1% belonged to middle/middle-low socioeconomic levels. Almost 50% were widows, but only 14.3% were living alone. Conclusion: The Pietà cohort is representative of the oldest-old Brazilian population. We believe the results of the study may contribute to increase our knowledge about healthy and pathological brain aging in the oldest-old. Key words: aging, epidemiology, brain, cognitive impairment, dementia, depression.Estudo Pietà: investigação epidemiológica sobre envelhecimento cerebral bem sucedido em Caeté (MG), Brasil. Métodos e características de base da coorte RESUMO Objetivos: Apresentar os métodos e as características sociodemográficas do projeto Pietà, estudo de base populacional que investiga o envelhecimento cerebral bem sucedido em uma coorte de idosos muito idosos. Método: O estudo foi conduzido em Caeté (MG). Em 2007, 1.251 indivíduos com 75+ anos residiam no município e foram convidados a participar. Os idosos responderam a um questionário de saúde geral e foram submetidos à avaliação clínica, neurológica, cognitiva, psiquiátrica e funcional. Um subgrupo realizou avaliação neuropsicológica, exames laboratoriais e ressonância magnética de crânio. Os participantes foram classificados em grupos com comprometimento cognitivo-não demência, demência, parkinsonismo, transtornos psiquiátricos ou envelhecimento cerebral bem sucedido. Resultados: Foram avaliados 639 idosos (51,1% da população-alvo; 64% mulheres), com idade 81,4±5,2 anos e escolaridade 2,7±2,6 anos. Quase 30%